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1.  The Effect of Intermittent Antenatal Iron Supplementation on Maternal and Infant Outcomes in Rural Viet Nam: A Cluster Randomised Trial 
PLoS Medicine  2013;10(6):e1001470.
Beverley-Anne Biggs and colleagues conduct a community-based cluster randomized trial in rural Viet Nam to compare the effect of antenatal iron-folic acid supplementation taken daily or twice weekly on maternal and infant outcomes.
Please see later in the article for the Editors' Summary
Anemia affects over 500 million women, and in pregnancy is associated with impaired maternal and infant outcomes. Intermittent antenatal iron supplementation is an attractive alternative to daily dosing; however, the impact of this strategy on infant outcomes remains unclear. We compared the effect of intermittent antenatal iron supplementation with daily iron supplementation on maternal and infant outcomes in rural Viet Nam.
Methods and Findings
This cluster randomised trial was conducted in Ha Nam province, Viet Nam. 1,258 pregnant women (<16 wk gestation) in 104 communes were assigned to daily iron–folic acid (IFA), twice weekly IFA, or twice weekly multiple micronutrient (MMN) supplementation. Primary outcome was birth weight. Mean birth weight was 3,148 g (standard deviation 416). There was no difference in the birth weights of infants of women receiving twice weekly IFA compared to daily IFA (mean difference [MD] 28 g; 95% CI −22 to 78), or twice weekly MMN compared to daily IFA (MD −36.8 g; 95% CI −82 to 8.2). At 32 wk gestation, maternal ferritin was lower in women receiving twice weekly IFA compared to daily IFA (geometric mean ratio 0.73; 95% CI 0.67 to 0.80), and in women receiving twice weekly MMN compared to daily IFA (geometric mean ratio 0.62; 95% CI 0.57 to 0.68), but there was no difference in hemoglobin levels. Infants of mothers who received twice weekly IFA had higher cognitive scores at 6 mo of age compared to those who received daily IFA (MD 1.89; 95% CI 0.23 to 3.56).
Twice weekly antenatal IFA or MMN did not produce a clinically important difference in birth weight, when compared to daily IFA supplementation. The significant improvement in infant cognitive outcomes at 6 mo of age following twice weekly antenatal IFA requires further exploration, and provides additional support for the use of intermittent, rather than daily, antenatal IFA in populations with low rates of iron deficiency.
Trial registration
Australia New Zealand Clinical Trials Registry 12610000944033
Please see later in the article for the Editors' Summary
Editors' Summary
Anemia is a common condition in which the blood does not supply the body with enough oxygen because of a low number of red blood cells or low levels of hemoglobin—the iron-containing pigment that enables red blood cells to carry oxygen. Iron deficiency is the most common cause of anemia worldwide and, according to the World Health Organization, affects over 2 billion people: half of all pregnant women and 40% of preschool children in low- and middle-income countries are thought to be anemic. Anemia contributes to 20% of all maternal deaths and is also linked to increased maternal morbidity, higher rates of preterm birth and low birth weight, and reduced infant survival, with potential long-term consequences for child growth and development. Identifying and treating iron deficiency anemia is therefore a global health priority.
Why Was This Study Done?
Daily iron–folic acid supplementation given from early in pregnancy is the standard recommended approach to prevent and treat anemia in pregnant women, but recently the World Health Organization recommended intermittent use because of poor compliance with daily regimes (because of side effects) and poor bowel absorption. However, the evidence from many of the studies used to support this recommendation was of poor quality, and so it remains unclear whether intermittent supplementation is as, or more, effective than daily supplementation, especially in lower income settings where antenatal testing for anemia is not readily available. So in this study, the researchers conducted a community-based cluster randomized trial (where groups of people are randomized, rather than individuals) in rural Viet Nam to compare the effect of antenatal iron–folic acid supplementation taken twice weekly (either alone, or in combination with other micronutrients) with daily iron–folic acid supplementation, on maternal and infant outcomes during the first six months of life.
What Did the Researchers Do and Find?
The researchers randomized 104 communes in Ha Nam Province, Viet Nam, and enrolled 1,258 women who were less than 16 weeks pregnant into the study between September and November 2010. Although the researchers intended to register the trial before the study started, registration was delayed by a month because the supplements arrived earlier than the researchers anticipated, and they thought it best to start recruiting at that time to avoid the Vietnamese New Year, when women might be travelling. Each woman was interviewed and had blood taken for hemoglobin and iron indices (ferritin) before receiving daily iron–folic acid supplementation (426 women), twice weekly iron–folic acid supplementation (425 women), or twice weekly iron–folic acid supplementation plus micronutrients (407 women). The women had follow-up assessments at 32 weeks gestation, delivery, and at six months postpartum: their infants were assessed at birth and at six months old.
The researchers found that at enrollment, the women's average hemoglobin concentration was 123 g/l, and 12.6% of the women were anemic. At 32 weeks gestation, 10.8% of the women were anemic, but there was no difference in hemoglobin levels between the three supplement groups. The average ferritin level was 75.6 µg/l at enrollment, with 2.2% of women iron deficient. Ferritin levels decreased from enrollment to 32 weeks gestation in all supplement groups but were lower in women who took twice weekly supplements. The researchers also found that birth weight (the primary outcome) was similar in all supplement groups, and there were also no differences in gestational age or in the risk of prematurity, stillbirth, or early neonatal death. At six months, there were also no differences in the levels of infant hemoglobin, prevalence of anemia, or growth rates. However, infants born to mothers in the twice weekly iron–folic acid group had improved cognitive development compared to infants born to mothers in the daily supplement group. Finally, the researchers found that adherence rates were significantly higher in the twice weekly iron–folic acid supplement group compared to the once daily regime.
What Do These Findings Mean?
These findings suggest that in an area of Southeast Asia with low anemia prevalence, once daily antenatal supplementation with iron–folic acid did not provide any benefits in birth weight or improved infant growth over twice weekly supplementation. Furthermore, twice weekly supplementation with iron–folic acid was associated with improved maternal adherence rates and also improved cognitive development in infants aged six months—a finding that requires further study and provides added support for the use of intermittent iron–folic acid supplementation over daily supplementation.
Additional Information
Please access these websites via the online version of this summary at
The World Health Organization website has comprehensive information on anemia, including a report of global estimates and the guideline Intermittent Iron and Folic Acid Supplementation in Non-Anaemic Pregnant Women
Wikipedia provides information on iron supplementation (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
PMCID: PMC3708703  PMID: 23853552
2.  Evaluation of Hemoglobin Concentration in Pregnancy and Correlation with Different Altitude: A Study from Balochistan Plateau of Pakistan 
Anemia refers to a condition having low hemoglobin concentration. Anemia is considered a major risk factor for unfavorable pregnancy outcomes. This is the first study describing the pattern of hemoglobin concentration during pregnancy and its relationship to areas of high and low altitudes in Balochistan (the largest of Pakistan’s four provinces). The main objective of this study was to observe hemoglobin levels and prevalence of anemia among pregnant women living in the high or low altitude areas of Balochistan.
A randomized survey was conducted and blood samples were collected from 132 healthy full term pregnant women subjects and 110 unmarried females. The subjects of the current study were selected from two different areas of Balochistan (Quetta and Uthal). Hemoglobin levels of the subjects were analyzed on Microlab 300 by Merck kit. Dietary status of the subjects was assessed based on simplified associated food frequency questionnaire. The factors effecting hemoglobin in full term pregnancy at different altitudes were multi gravidity/parity (increased number of pregnancies/children), age, socio-economic and educational status.
Anemia was highly prevalent in low-altitude region (68.33%). We found statistically significant difference in mean hemoglobin level at high-altitude region (11.81 ± 1.02) and low-altitude region (10.20 ± 1.28) in pregnant females of Balochistan plateau (P < 0.001). Higher maternal age (> 35 years) has shown significantly higher anemic frequency at both high (57.89%; p < 0.002) and low (41.46%; p = 0.067) altitudes. A balanced-diet that is rich in meat products has also shown significant correlation with reduced incidences of anemia among pregnant women at both altitudes.
Hemoglobin concentration increases in the body with elevated altitudes and, thus, anemia was less frequent at high-altitude region. Factors affecting hemoglobin concentration in full term pregnancy at different altitudes included old maternal age, low body-mass index, education and diet.
PMCID: PMC4347023  PMID: 25741391
Anemia; altitude; diet; hemoglobin; pregnancy.
3.  Anemia prevalence and risk factors in pregnant women in an urban area of Pakistan 
Food and nutrition bulletin  2008;29(2):132-139.
Anemia affects almost two-thirds of pregnant women in developing countries and contributes to maternal morbidity and mortality and to low birthweight.
To determine the prevalence of anemia and the dietary and socioeconomic factors associated with anemia in pregnant women living in an urban community setting in Hyderabad, Pakistan.
This was a prospective, observational study of 1,369 pregnant women enrolled at 20 to 26 weeks of gestation and followed to 6 weeks postpartum. A blood sample was obtained at enrollment to determine hemoglobin levels. Information on nutritional knowledge, attitudes, and practice and dietary history regarding usual food intake before and during pregnancy were obtained by trained interviewers within 1 week of enrollment.
The prevalence of anemia (defined by the World Health Organization as hemoglobin < 11.0 g/dL) in these subjects was 90.5%; of these, 75.0% had mild anemia (hemoglobin from 9.0 to 10.9 g/dL) and 14.8% had moderate anemia (hemoglobin from 7.0 to 8.9 g/dL). Only 0.7% were severely anemic (hemoglobin < 7.0 g/dL). Nonanemic women were significantly taller, weighed more, and had a higher body mass index. Multivariate analysis after adjustment for education, pregnancy history, iron supplementation, and height showed that drinking more than three cups of tea per day before pregnancy (adjusted prevalence odds ratio [aPOR], 3.2; 95% confidence interval [CI], 1.3 to 8.0), consumption of clay or dirt during pregnancy (aPOR, 3.7; 95% CI, 1.1 to 12.3), and never consuming eggs or consuming eggs less than twice a week during pregnancy (aPOR, 1.7; 95% CI, 1.1 to 2.5) were significantly associated with anemia. Consumption of red meat less than twice a week prior to pregnancy was marginally associated with anemia (aPOR, 1.2; 95% CI, 0.8 to 1.8) but was significantly associated with lower mean hemoglobin concentrations (9.9 vs. 10.0 g/dL, p = .05) during the study period. A subanalysis excluding women with mild anemia found similar associations to those of the main model, albeit even stronger.
A high percentage of women at 20 to 26 weeks of pregnancy had mild to moderate anemia. Pica, tea consumption, and low intake of eggs and red meat were associated with anemia. Women of childbearing age should be provided nutritional education regarding food sources of iron, especially prior to becoming pregnant, and taught how food choices can either enhance or interfere with iron absorption.
PMCID: PMC3917507  PMID: 18693477
Anemia; developing countries; pregnancy
4.  Evaluation of a portable hemoglobin photometer in pregnant women in a high altitude area: a pilot study 
BMC Public Health  2009;9:228.
Anemia is a widespread public health problem associated with an increased risk of morbidity and mortality, especially in pregnant women. This study examined the agreement between a portable hemoglobin photometer and a laboratory analyzer in determining hemoglobin level in pregnant women.
This study recruited 69 pregnant women in Tibet, China. Capillary blood samples were taken to measure hemoglobin concentration using the hemoglobin photometer and the laboratory analyzer. Limit of agreement, concordance and intraclass correlation coefficient were used to evaluate the agreement. Laboratory measurement was considered as the standard reference method. Sensitivity and specificity were calculated to assess the error in screening for anemia.
Mean difference between the two methods was -2.1 g/l. wide 95% limits of agreement were found (-22.6 g/l to 18.4 g/l). The intraclass correlation coefficient was 0.795, and concordance correlation coefficient was 0.793. Sensitivity and specificity were 94.9% and 76.7% respectively. Positive predictive value was 84.1%, and negative predictive value was 92.0%.
This hemoglobin photometer is not recommended for determining hemoglobin concentration in pregnancy in a high altitude area.
PMCID: PMC2717084  PMID: 19591672
5.  Maternal Hemoglobin Levels during Pregnancy and their Association with Birth Weight of Neonates 
Back ground
Anemia in pregnancy is associated with increased rates of maternal and perinatal mortality, premature delivery, low birth weight, and other adverse outcomes
Materials and Methods
A prospective study was conducted on 1405 Iranian pregnant women who delivered during 2015. Blood was collected from all the subjects to measure the hemoglobin (Hb) during 16-19 weeks, 22-24 weeks, and 34-36 weeks of gestation. According to the level of hemoglobin, it is divided into 4 groups. Group 1; Hb > 10.1 gm/100ml (control group), Group 2; Hb= 8.1-10 gm/100ml (mild anemia) Group 3; Hb= 6.5-8 gm/100ml (moderate anemia) Group 4; Hb <6.5 gm/100ml (severe anemia). After delivery, the neonates were weighted within 24 hours after birth. Maternal hemoglobin and birth weights were compared.
The anemia prevalence was 20.2% (Hb<10g/dl). Out of them, 16.2 % hadmoderate anemia (Hb=6.5-8 g/dl) and 83.8% had mild anemia (Hb=8.1-10 g/dl). Severe anemia did not detect in pregnant women. The hemoglobin levels in non anemic group showed a drop in the second trimester. Pregnant women with hemoglobin less than 10 g/dl, considered as anemic gave birth to neonates with birth weight of 2.6kg, while pregnant women with higher hemoglobin level (>10 g/dl), considered as normal gave birth to heavier and normal babies (3.3 kg). The severity of anemia during three trimesters was closely associated with birth weight of newborns.
The low hemoglobin values during three trimesters of pregnancy were associated with low birth weight in Iran. The anemia can lead to intra uterine growth retardation.
PMCID: PMC4779156  PMID: 26985354
Hemoglobin Level; Birth Weight; Pregnancy
6.  Prevalence and risk factors of anemia among pregnant women attending a high-volume tertiary care center for delivery 
The aim of this study was to identify the prevalence of anemia and predisposing factors contributing to anemia in pregnant women prior to delivery.
Material and Methods
A retrospective case-control study was conducted on 1221 women who delivered between 37 and 42 weeks of gestation between July 2014 and January 2015. Data on the subjects’ socioeconomic and demographic characteristics, pregnancy outcomes, and hemoglobin levels within 24 h prior to delivery were collected. The study population was divided into two groups on the basis of the presence of anemia within 24 h prior to delivery. Anemia was defined as a hemoglobin level of <11 g/dL. The prevalence of pre-delivery anemia was estimated, and antenatal predictors of anemia were determined using multivariate logistic regression analysis.
The prevalence of anemia in women attending our center for delivery was 41.6% [95% confidence interval (CI) =38.84–44.37]. After multivariate logistic regression analysis, parity >3 [odds ratio (OR) =1.82, 95% CI=1.24–2.96, p=0.002], illiterate (OR=2.23, 95% CI=1.35–3.45, p=0.001) and primary educational level (OR=2.01, 95% CI=1.28–3.39, p=0.008), household monthly income per person <250 Turkish liras (OR=2.34, 95% CI=1.49–3.89, p<0.001), first admission at second (OR=1.63, 95% CI=1.24–2.81, p=0.006) and third trimester (OR=2.45, 95% CI=1.41–4.06, p<0.001), number of antenatal visits <5 (OR=1.45, 95% CI=10.5–2.11) and 5–10 (OR=1.3, 95% CI=1.03–2.09), duration of iron supplementation <3 months (OR=2.62, 95% CI=1.51–4.17) and 3–6 months (OR=1.68, 95% CI=1.13–2.91), and occurrence of preeclampsia (OR=1.55, 95% CI=1.03–2.1, p=0.041) were independently associated with anemia.
Socioeconomic determinants constitute most of the anemia cases and, hence, should be considered as major risk factors of anemia in women attending for delivery at term.
PMCID: PMC4664215  PMID: 26692774
Anemia; delivery; perinatal outcome; pregnancy; socioeconomic factors
7.  Maternal and Perinatal Outcomes in Second Hemoglobin Measurement in Nonanemic Women at First Booking: Effect of Altitude of Residence in Peru 
ISRN Obstetrics and Gynecology  2012;2012:368571.
Objective. To determine changes in hemoglobin concentration at second measurements after a normal hemoglobin concentration was detected at first booking during pregnancy at low and at high altitudes. Methods. This is a secondary analysis of a large database obtained from the Perinatal Information System in Peru which includes 379,816 pregnant women and their babies from 43 maternity units in Peru. Results. Most women remained with normal hemoglobin values at second measurement (75.1%). However, 21.4% of women became anemic at the second measurement. In all, 2.8% resulted with moderate/severe anemia and 3.5% with erythrocytosis (Hb>14.5 g/dL). In all cases Hb was higher as altitude increased. Risk for moderate/severe anemia increased associated with higher gestational age at second measurement of hemoglobin, BMI <19.9 kg/m2, living without partner, <5 antenatal care visits, first parity, multiparity, and preeclampsia. Lower risk for moderate/severe anemia was observed with normal high Hb level at first booking living at moderate and high altitude, and high BMI. Conclusion. Prevalence of anemia increases as pregnancy progress, and that a normal value at first booking may not be considered sufficient as Hb values should be observed throughout pregnancy. BMI was a risk for anemia in a second measurement.
PMCID: PMC3345214  PMID: 22577573
8.  Maternal Hemoglobin Concentration and Pregnancy Outcome: A Study of the Effects of Elevation in El Alto, Bolivia 
Iron-deficiency anemia is often under-diagnosed in developing countries, specifically in pregnant populations in regions of high altitude. Hemoglobin levels are not consistently adjusted for elevation, and therefore many anemic patients are left undiagnosed. The purpose of this study was to incorporate current parameters for diagnosing anemia in pregnancy at high altitudes, and to evaluate the effects of appropriately adjusted hemoglobin concentrations on pregnancy outcome. A few studies have examined the effect of elevation on hemoglobin status, and other studies have considered the effects of anemia of pregnancy; however, there is a lack of data demonstrating that altitude-adjusted hemoglobin levels accurately predict pregnancy outcome. Using the Student t-Test, multiple linear regression, and ANOVA statistical analyses, various factors of pregnancy outcome were compared between anemic and non-anemic groups, as defined by hemoglobin cut-off levels adjusted for trimester of pregnancy and altitude. When appropriate adjustments were used, maternal anemia was associated with lower infant Apgar scores at both one minute and five minutes after birth, as well as complication of labor, lower gestational age at birth, and higher parity. This study demonstrates the importance of altitude and trimester specific adjustments to maternal hemoglobin levels in order to accurately diagnose anemia in pregnancy. In addition, a clear correlation is seen between maternal hemoglobin level and pregnancy outcome.
PMCID: PMC3296152  PMID: 22399871
Iron-Deficiency Anemia; Pregnancy; Bolivia; Elevation; Altitude; Hemoglobin
9.  The Association of Parasitic Infections in Pregnancy and Maternal and Fetal Anemia: A Cohort Study in Coastal Kenya 
Relative contribution of these infections on anemia in pregnancy is not certain. While measures to protect pregnant women against malaria have been scaling up, interventions against helminthes have received much less attention. In this study, we determine the relative impact of helminthes and malaria on maternal anemia.
A prospective observational study was conducted in coastal Kenya among a cohort of pregnant women who were recruited at their first antenatal care (ANC) visit and tested for malaria, hookworm, and other parasitic infections and anemia at enrollment. All women enrolled in the study received presumptive treatment with sulfadoxine-pyrimethamine, iron and multi-vitamins and women diagnosed with helminthic infections were treated with albendazole. Women delivering a live, term birth, were also tested for maternal anemia, fetal anemia and presence of infection at delivery.
Principal Findings
Of the 706 women studied, at the first ANC visit, 27% had moderate/severe anemia and 71% of women were anemic overall. The infections with highest prevalence were hookworm (24%), urogenital schistosomiasis (17%), trichuria (10%), and malaria (9%). In adjusted and unadjusted analyses, moderate/severe anemia at first ANC visit was associated with the higher intensities of hookworm and P. falciparum microscopy-malaria infections. At delivery, 34% of women had moderate/severe anemia and 18% of infants' cord hemoglobin was consistent with fetal anemia. While none of the maternal infections were significantly associated with fetal anemia, moderate/severe maternal anemia was associated with fetal anemia.
More than one quarter of women receiving standard ANC with IPTp for malaria had moderate/severe anemia in pregnancy and high rates of parasitic infection. Thus, addressing the role of co-infections, such as hookworm, as well as under-nutrition, and their contribution to anemia is needed.
Author Summary
International guidelines recommend routine prevention and treatments which are safe and effective during pregnancy to reduce hookworm, malaria and other infections among pregnant women living in geographic areas where these infections are prevalent. Despite their effectiveness, programs to address common infections such as hookworm, schistosomiasis and malaria during pregnancy have not been widely adopted. Hookworm, malaria and other infections have been associated with anemia in children, but the studies on the impact of these infections on anemia in pregnancy have not been as clear. This study was undertaken to evaluate the prevalence of parasitic infections among women attending antenatal care which provided the nationally recommended malaria preventive treatment program in coastal Kenya. At the first ANC visit, more than 70% of women were anemic, nearly one-fourth had hookworm and about 10% had malaria. Women with high levels of hookworm or malaria infections were at risk of anemia.
PMCID: PMC3937317  PMID: 24587473
10.  Threshold Haemoglobin Levels and the Prognosis of Stable Coronary Disease: Two New Cohorts and a Systematic Review and Meta-Analysis 
PLoS Medicine  2011;8(5):e1000439.
Anoop Shah and colleagues performed a retrospective cohort study and a systematic review, and show evidence that in people with stable coronary disease there were threshold hemoglobin values below which mortality increased in a graded, continuous fashion.
Low haemoglobin concentration has been associated with adverse prognosis in patients with angina and myocardial infarction (MI), but the strength and shape of the association and the presence of any threshold has not been precisely evaluated.
Methods and findings
A retrospective cohort study was carried out using the UK General Practice Research Database. 20,131 people with a new diagnosis of stable angina and no previous acute coronary syndrome, and 14,171 people with first MI who survived for at least 7 days were followed up for a mean of 3.2 years. Using semi-parametric Cox regression and multiple adjustment, there was evidence of threshold haemoglobin values below which mortality increased in a graded continuous fashion. For men with MI, the threshold value was 13.5 g/dl (95% confidence interval [CI] 13.2–13.9); the 29.5% of patients with haemoglobin below this threshold had an associated hazard ratio for mortality of 2.00 (95% CI 1.76–2.29) compared to those with haemoglobin values in the lowest risk range. Women tended to have lower threshold haemoglobin values (e.g, for MI 12.8 g/dl; 95% CI 12.1–13.5) but the shape and strength of association did not differ between the genders, nor between patients with angina and MI. We did a systematic review and meta-analysis that identified ten previously published studies, reporting a total of only 1,127 endpoints, but none evaluated thresholds of risk.
There is an association between low haemoglobin concentration and increased mortality. A large proportion of patients with coronary disease have haemoglobin concentrations below the thresholds of risk defined here. Intervention trials would clarify whether increasing the haemoglobin concentration reduces mortality.
Please see later in the article for the Editors' Summary
Editors' Summary
Coronary artery disease is the main cause of death in high-income countries and the second most common cause of death in middle- and low-income countries, accounting for 16.3%, 13.9%, and 9.4% of all deaths, respectively, in 2004. Many risks factors, such as high blood pressure and high blood cholesterol level, are known to be associated with coronary artery disease, and prevention and treatment of such factors remains one of the key strategies in the management of coronary artery disease. Recent studies have suggested that low hemoglobin may be associated with mortality in patients with coronary artery disease. Therefore, using blood hemoglobin level as a prognostic biomarker for patients with stable coronary artery disease may be of potential benefit especially as measurement of hemoglobin is almost universal in such patients and there are available interventions that effectively increase hemoglobin concentration.
Why was This Study Done?
Much more needs to be understood about the relationship between low hemoglobin and coronary artery disease before hemoglobin levels can potentially be used as a clinical prognostic biomarker. Previous studies have been limited in their ability to describe the shape of this relationship—which means that it is uncertain whether there is a “best” hemoglobin threshold or a continuous graded relationship from “good” to “bad”—to assess gender differences, and to compare patients with angina or who have experienced previous myocardial infarction. In order to inform these knowledge gaps, the researchers conducted a retrospective analysis of patients from a prospective observational cohort as well as a systematic review and meta-analysis (statistical analysis) of previous studies.
What Did the Researchers Do and Find?
The researchers conducted a systematic review and meta-analysis of previous studies and found ten relevant studies, but none evaluated thresholds of risk, only linear relationships.
The researchers carried out a new study using the UK's General Practice Research Database—a national research tool that uses anonymized electronic clinical records of a representative sample of the UK population, with details of consultations, diagnoses, referrals, prescriptions, and test results—as the basis for their analysis. They identified and collected information from two cohorts of patients: those with new onset stable angina and no previous acute coronary syndrome; and those with a first myocardial infarction (heart attack). For these patients, the researchers also looked at all values of routinely recorded blood parameters (including hemoglobin) and information on established cardiovascular risk factors, such as smoking. The researchers followed up patients using death of any cause as a primary endpoint and put this data into a statistical model to identify upper and lower thresholds of an optimal hemoglobin range beyond which mortality risk increased.
The researchers found that there was a threshold hemoglobin value below which mortality continuously increased in a graded manner. For men with myocardial infarction, the threshold value was 13.5 g/dl: 29.5% of patients had hemoglobin below this threshold and had a hazard ratio for mortality of 2.00 compared to those with hemoglobin values in the lowest risk range. Women had a lower threshold hemoglobin value than men: 12.8 g/dl for women with myocardial infarction, but the shape and strength of association did not differ between the genders, or between patients with angina and myocardial infarction.
What Do These Findings Mean?
These findings suggest that there are thresholds of hemoglobin that are associated with increased risk of mortality in patients with angina or myocardial infarction. A substantial proportion of patients (15%–30%) have a hemoglobin level that places them at markedly higher risk of death compared to patients with lowest risk hemoglobin levels and importantly, these thresholds are higher than clinicians might anticipate—and are remarkably similar to World Health Organization anemia thresholds of 12 g/dl for women and 13 g/dl for men. Despite the limitations of these observational findings, this study supports the rationale for conducting future randomized controlled trials to assess whether hemoglobin levels are causal and whether clinicians should intervene to increase hemoglobin levels, for example by oral iron supplementation.
Additional Information
Please access these Web sites via the online version of this summary at
Wikipedia provides information about hemoglobin (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
The World Health Organization provides an overview of the global prevalence of coronary artery disease, a factsheet on the top ten causes of death, as well as information on anemia
PMCID: PMC3104976  PMID: 21655315
11.  Exercise Capacity and Selected Physiological Factors by Ancestry and Residential Altitude: Cross-Sectional Studies of 9–10-Year-Old Children in Tibet 
High Altitude Medicine & Biology  2014;15(2):162-169.
Bianba, Sveinung Bernsten, Lars Bo Andersen, Hein Stegum, Ouzhuluobu, Per Nafstad, Tianyi Wu, and Espen Bjertness. Exercise capacity and selected physiological factors by ancestry and residential altitude—Cross-sectional studies of 9–10-year-old children in Tibet. High Alt Med Biol. 15:162–169, 2014.—Aim: Several physiological compensatory mechanisms have enabled Tibetans to live and work at high altitude, including increased ventilation and pulmonary diffusion capacity, both of which serve to increase oxygen transport in the blood. The aim of the present study was to compare exercise capacity (maximal power output) and selected physiological factors (arterial oxygen saturation and heart rate at rest and during maximal exercise, resting hemoglobin concentration, and forced vital capacity) in groups of native Tibetan children living at different residential altitudes (3700 vs. 4300 m above sea level) and across ancestry (native Tibetan vs. Han Chinese children living at the same altitude of 3700 m).
Methods: A total of 430 9–10-year-old native Tibetan children from Tingri (4300 m) and 406 native Tibetan- and 406 Han Chinese immigrants (77% lowland-born and 33% highland-born) from Lhasa (3700 m) participated in two cross-sectional studies. The maximal power output (Wmax) was assessed using an ergometer cycle.
Results: Lhasa Tibetan children had a 20% higher maximal power output (watts/kg) than Tingri Tibetan and 4% higher than Lhasa Han Chinese. Maximal heart rate, arterial oxygen saturation at rest, lung volume, and arterial oxygen saturation were significantly associated with exercise capacity at a given altitude, but could not fully account for the differences in exercise capacity observed between ancestry groups or altitudes.
Conclusions: The superior exercise capacity in native Tibetans vs. Han Chinese may reflect a better adaptation to life at high altitude. Tibetans at the lower residential altitude of 3700 m demonstrated a better exercise capacity than residents at a higher altitude of 4300 m when measured at their respective residential altitudes. Such altitude- or ancestry-related difference could not be fully attributed to the physiological factors measured.
PMCID: PMC4074746  PMID: 24836751
high altitude; adaptation; maximal exercise; arterial oxygen saturation; hemoglobin
12.  Re-Visiting Trichuris trichiura Intensity Thresholds Based on Anemia during Pregnancy 
The intensity categories, or thresholds, currently used for Trichuris trichiura (ie. epg intensities of 1–999 (light); 1,000–9,999 epg (moderate), and ≥10,000 epg (heavy)) were developed in the 1980s, when there were little epidemiological data available on dose-response relationships. This study was undertaken to determine a threshold for T. trichiura-associated anemia in pregnant women and to describe the implications of this threshold in terms of the need for primary prevention and chemotherapeutic interventions.
Methodology/Principal Findings
In Iquitos, Peru, 935 pregnant women were tested for T. trichiura infection in their second trimester of pregnancy; were given daily iron supplements throughout their pregnancy; and had their blood hemoglobin levels measured in their third trimester of pregnancy. Women in the highest two T. trichiura intensity quintiles (601–1632 epg and ≥1633 epg) had significantly lower mean hemoglobin concentrations than the lowest quintile (0–24 epg). They also had a statistically significantly higher risk of anemia, with adjusted odds ratios of 1.67 (95% CI: 1.02, 2.62) and 1.73 (95% CI: 1.09, 2.74), respectively.
This analysis provides support for categorizing a T. trichiura infection ≥1,000 epg as ‘moderate’, as currently defined by the World Health Organization. Because this ‘moderate’ level of T. trichiura infection was found to be a significant risk factor for anemia in pregnant women, the intensity of Trichuris infection deemed to cause or aggravate anemia should no longer be restricted to the ‘heavy’ intensity category. It should now include both ‘heavy’ and ‘moderate’ intensities of Trichuris infection. Evidence-based deworming strategies targeting pregnant women or populations where anemia is of concern should be updated accordingly.
Author Summary
Infection by the soil-transmitted helminth Trichuris trichiura is defined as ‘light’, ‘moderate’ and ‘heavy’ depending on its intensity. However, these intensity categories were developed in the 1980s, before any epidemiological data were available on the association between specific T. trichiura infection intensities and adverse health outcomes. Here, we re-analyzed data from a study of T. trichiura infection and anemia in pregnant women to determine the threshold (i.e. the lowest infection intensity) associated with an increased risk of anemia. Women with T. trichiura infections of intensities ranging from 601 to 1632 eggs per gram of feces (epg) (ie. a ‘moderate’ level of intensity) had a significantly higher prevalence of anemia and a significantly lower hemoglobin level than the reference group (i.e. women with T. trichiura infections of intensities ranging between 0 and 24 epg). This finding contrasts with the common belief that only ‘heavy’ T. trichiura infection (10,000 epg and above) can cause anemia.
PMCID: PMC3441397  PMID: 23029572
13.  Anemia among pregnant women in Southeast Ethiopia: prevalence, severity and associated risk factors 
BMC Research Notes  2014;7:771.
Anemia is a significant public health problem in developing countries, particularly in pregnant women. It may complicate pregnancy, sometimes resulting in tragic outcomes. There is a lack of information on the magnitude of anemia among pregnant women in Southeast Ethiopia. The aim of this study is, therefore, to determine the prevalence of anemia and assess associated factors among pregnant women attending antenatal care (ANC) at Bisidimo Hospital in Southeast Ethiopia.
A facility-based cross-sectional study, involving 258 pregnant women, was conducted from March to June 2013. Socio-demographic, medical and obstetric data of the study participants were collected using structured questionnaire. Hemoglobin was measured using a hematology analyzer and faecal specimens were examined to detect intestinal parasites. Anemia in pregnancy was defined as hemoglobin <11 g/dl.
Overall, prevalence of anemia was 27.9%, of which 55% had mild anemia. Rural residence (AOR =3.3, 95% CI: 1.5-7.4), intestinal parasitic infection (IPI) (AOR = 2.5, 95% CI: 1.3-4.8) and history of heavy cycle (AOR =2.7, 95% CI: 1.3-1.7) were predictors of anemia.
This study showed moderate prevalence of anemia among the pregnant women, with a sizable proportion having severe anemia. Routine testing of pregnant women for IPIs and creating awareness on factors predisposing to anemia is recommended.
PMCID: PMC4223834  PMID: 25362931
Anemia; Associated factors; Pregnant women; Southeast Ethiopia
14.  Prevalence of HIV and anemia among pregnant women 
Human immunodeficiency virus (HIV) prevalence is high among rural dwellers and pregnant women.
This study aims to determine the prevalence of HIV and anemia among pregnant women attending antenatal clinic in rural community of Okada, Edo State, Nigeria.
Patients and Methods:
Anticoagulated blood and sera samples were obtained from 480 women consisting of 292 pregnant and 188 non-pregnant women. Antibodies to HIV were detected in the sera samples and hemoglobin concentration of the anticoagulated blood specimens were determined using standard techniques. Anemia was defined as hemoglobin concentration <11g/dl for pregnant women and <12g/dl for non-pregnant women.
Pregnancy was not a risk factor for acquiring HIV infection (pregnant vs. non-pregnant: 10.2% vs. 13.8%; OR=0.713, 95% CI=0.407, 1.259, P = 0.247). The prevalence of HIV was significantly (P = 0.005 and P = 0.025) higher in the age group 10-20 years and 21 – 30 years among pregnant and non-pregnant women respectively. Pregnancy was a risk factor for acquiring anemia (OR=1.717, 95% CI=1.179, 2.500, P = 0.006). Only the age of pregnant women significantly (P = 0.004) affected the prevalence of anemia inversely.
The prevalence of HIV and anemia among pregnant women were 10.2% and 49.3% respectively. Pregnancy was associated with anemia. Interventions by appropriate agencies are advocated to reduce associated sequelae.
PMCID: PMC3271417  PMID: 22363076
Pregnancy; HIV; anemia; rural community; Nigeria
15.  Khat Chewing and Restrictive Dietary Behaviors Are Associated with Anemia among Pregnant Women in High Prevalence Rural Communities in Eastern Ethiopia 
PLoS ONE  2013;8(11):e78601.
Anemia affects a high proportion of pregnant women in the developing countries. Factors associated with it vary in context. This study aimed to determine the prevalence and predictors of anemia among pregnant women in the rural eastern Ethiopia.
A community-based cross-sectional study was done on 1678 pregnant women who were selected by a cluster random sampling technique. A pregnant woman was identified as anemic if her hemoglobin concentration was <11 g/dl. Data were collected in a community-based setting. Multilevel mixed effect logistic regression was used to determine the adjusted odds ratios (AOR) with 95% confidence intervals (CI) for the predictors of anemia.
Anemia was observed among 737(43.9%) of the 1678 pregnant women studied (95% CI 41.5%–46.3%). After controlling for the confounders, the risk of anemia was 29% higher in the women who chewed khat daily than those who sometimes or never did so (AOR, 1.29; 95% CI, 1.02–1.62). The study subjects with restrictive dietary behavior (reduced either meal size or frequency) had a 39% higher risk of anemia compared to those without restrictive dietary behavior (AOR, 1.39; 95% CI, 1.02–1.88). The risk of anemia was increased by 68% (AOR, 1.68; 95% CI, 1.15–2.47), and 60% (AOR, 1.60; 95% CI, 1.08–2.37) in parity levels of 2 births and 3 births, respectively. Compared to the first trimester, the risk of anemia was higher by two-fold (AOR, 2.09; 95% CI, 1.46–3.00) in the second trimester and by four-fold (AOR, 4.23; 95% CI, 2.97–6.02) in the third trimester.
In this study, two out of five women were anemic. Chewing khat and restrictive dietary habits that are associated with anemia in the setting should be addressed through public education programs. Interventions should also focus on the women at higher parity levels and those who are in advanced stages of pregnancy.
PMCID: PMC3817221  PMID: 24223828
16.  Prevalence of Anemia and Associated Factors among Pregnant Women in North Western Zone of Tigray, Northern Ethiopia: A Cross-Sectional Study 
Background. Anemia affects the lives of more than 2 billion people globally, accounting for over 30% of the world's population. Anemia is a global public health problem occurring at all stages of the life cycle but the burden of the problem is higher in pregnant women particularly in developing countries. The aim of this study was to determine the prevalence of anemia and associated factors among pregnant women attending antenatal clinics in north western zone of Tigray, northern Ethiopia. Methods. A facility based cross-sectional study was employed. A systematic random sampling procedure was employed to select 714 pregnant women who were attending antenatal clinics in health facilities found in the study area from April to May 2014. The data was entered and analyzed using Epi-info version 3.5.1 and SPSS version 20.0 statistical software, respectively. Logistic regression analysis was used to identify factors associated with anemia among the study participants. All tests were two-sided and p value < 0.05 was considered statistically significant. Results. The overall prevalence of anemia (hemoglobin < 11 g/dL) among the pregnant women was 36.1% (95% CI = 32.7%–39.7%) of which 58.5% were mildly, 35.7% moderately, and 5.8% severely anemic. In pregnant women, rural residence (AOR = 1.75, 95% CI = 1.01–3.04), no education/being illiterate (AOR = 1.56, 95% CI = 1.03–2.37), absence of iron supplementation during pregnancy (AOR = 2.76, 95% CI = 1.92–5.37), and meal frequency of less than two times per day (AOR = 2.28, 95% CI = 1.06–4.91) were the independent predictors for increased anemia among the pregnant women. Conclusions. Anemia was found to be moderate public health problem in the study area. Residence, educational status, iron supplementation during pregnancy, and meal frequency per day were statistically associated with anemia among the pregnant women. Awareness creation and nutrition education on the importance of taking iron supplementation and nutritional counseling on consumption of extra meal and iron-rich foods during pregnancy are recommended to prevent anemia in the pregnant women.
PMCID: PMC4475559  PMID: 26137321
17.  Does Smoke from Biomass Fuel Contribute to Anemia in Pregnant Women in Nagpur, India? A Cross-Sectional Study 
PLoS ONE  2015;10(5):e0127890.
Anemia affects upwards of 50% of pregnant women in developing countries and is associated with adverse outcomes for mother and child. We hypothesized that exposure to smoke from biomass fuel – which is widely used for household energy needs in resource-limited settings – could exacerbate anemia in pregnancy, possibly as a result of systemic inflammation.
To evaluate whether exposure to smoke from biomass fuel (wood, straw, crop residues, or dung) as opposed to clean fuel (electricity, liquefied petroleum gas, natural gas, or biogas) is an independent risk factor for anemia in pregnancy, classified by severity.
A secondary analysis was performed using data collected from a rural pregnancy cohort (N = 12,782) in Nagpur, India in 2011-2013 as part of the NIH-funded Maternal and Newborn Health Registry Study. Multinomial logistic regression was used to estimate the effect of biomass fuel vs. clean fuel use on anemia in pregnancy, controlling for maternal age, body mass index, education level, exposure to household tobacco smoke, parity, trimester when hemoglobin was measured, and receipt of prenatal iron and folate supplements.
The prevalence of any anemia (hemoglobin < 11 g/dl) was 93% in biomass fuel users and 88% in clean fuel users. Moderate-to-severe anemia (hemoglobin < 10 g/dl) occurred in 53% and 40% of the women, respectively. Multinomial logistic regression showed higher relative risks of mild anemia in pregnancy (hemoglobin 10-11 g/dl; RRR = 1.38, 95% CI = 1.19-1.61) and of moderate-to-severe anemia in pregnancy (RRR = 1.79, 95% CI = 1.53-2.09) in biomass fuel vs. clean fuel users, after adjusting for covariates.
In our study population, exposure to biomass smoke was associated with higher risks of mild and moderate-to-severe anemia in pregnancy, independent of covariates.
Trial Registration NCT 01073475
PMCID: PMC4449186  PMID: 26024473
18.  Major Burden of Severe Anemia from Non-Falciparum Malaria Species in Southern Papua: A Hospital-Based Surveillance Study 
PLoS Medicine  2013;10(12):e1001575.
Ric Price and colleagues use hospital-based surveillance data to estimate the risk of severe anemia and mortality associated with endemic Plasmodium species in southern Papua, Indonesia.
Please see later in the article for the Editors' Summary
The burden of anemia attributable to non-falciparum malarias in regions with Plasmodium co-endemicity is poorly documented. We compared the hematological profile of patients with and without malaria in southern Papua, Indonesia.
Methods and Findings
Clinical and laboratory data were linked for all patients presenting to a referral hospital between April 2004 and December 2012. Data were available on patient demographics, malaria diagnosis, hemoglobin concentration, and clinical outcome, but other potential causes of anemia could not be identified reliably. Of 922,120 patient episodes (837,989 as outpatients and 84,131 as inpatients), a total of 219,845 (23.8%) were associated with a hemoglobin measurement, of whom 67,696 (30.8%) had malaria. Patients with P. malariae infection had the lowest hemoglobin concentration (n = 1,608, mean = 8.93 [95% CI 8.81–9.06]), followed by those with mixed species infections (n = 8,645, mean = 9.22 [95% CI 9.16–9.28]), P. falciparum (n = 37,554, mean = 9.47 [95% CI 9.44–9.50]), and P. vivax (n = 19,858, mean = 9.53 [95% CI 9.49–9.57]); p-value for all comparisons <0.001. Severe anemia (hemoglobin <5 g/dl) was present in 8,151 (3.7%) patients. Compared to patients without malaria, those with mixed Plasmodium infection were at greatest risk of severe anemia (adjusted odds ratio [AOR] 3.25 [95% CI 2.99–3.54]); AORs for severe anaemia associated with P. falciparum, P. vivax, and P. malariae were 2.11 (95% CI 2.00–2.23), 1.87 (95% CI 1.74–2.01), and 2.18 (95% CI 1.76–2.67), respectively, p<0.001. Overall, 12.2% (95% CI 11.2%–13.3%) of severe anemia was attributable to non-falciparum infections compared with 15.1% (95% CI 13.9%–16.3%) for P. falciparum monoinfections. Patients with severe anemia had an increased risk of death (AOR = 5.80 [95% CI 5.17–6.50]; p<0.001). Not all patients had a hemoglobin measurement, thus limitations of the study include the potential for selection bias, and possible residual confounding in multivariable analyses.
In Papua P. vivax is the dominant cause of severe anemia in early infancy, mixed P. vivax/P. falciparum infections are associated with a greater hematological impairment than either species alone, and in adulthood P. malariae, although rare, is associated with the lowest hemoglobin concentration. These findings highlight the public health importance of integrated genus-wide malaria control strategies in areas of Plasmodium co-endemicity.
Please see later in the article for the Editors' Summary
Editors' Summary
Malaria—a mosquito-borne parasitic disease—is a global public health problem. Five parasites cause malaria—Plasmodium falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi. Of these, P. vivax is the commonest and most widely distributed, whereas P. falciparum causes the most deaths—about a million every year. All these parasites enter their human host when an infected mosquito takes a blood meal. The parasites migrate to the liver where they replicate and mature into a parasitic form known as merozoites. After 8–9 days, the merozoites are released from the liver cells and invade red blood cells where they replicate rapidly before bursting out and infecting more red blood cells. Malaria's recurring flu-like symptoms are caused by this cyclical increase in parasites in the blood. Malaria needs to be treated promptly with antimalarial drugs to prevent the development of potentially fatal complications. Infections with P. falciparum in particular can cause anemia (a reduction in red blood cell numbers) and can damage the brain and other vital organs by blocking the capillaries that supply these organs with blood.
Why Was This Study Done?
It is unclear what proportion of anemia is attributable to non-falciparum malarias in regions of the world where several species of malaria parasite are always present (Plasmodium co-endemicity). Public health officials in such regions need to know whether non-falciparum malarias are a major cause of anemia when designing malaria control strategies. If P. vivax, for example, is a major cause of anemia in an area where P. vivax and P. falciparum co-exist, then any malaria control strategies that are implemented need to take into account the biological differences between the parasites. In this hospital-based cohort study, the researchers investigate the burden of severe anemia from the endemic Plasmodium species in southern Papua, Indonesia.
What Did the Researchers Do and Find?
The researchers used hospital record numbers to link clinical and laboratory data for patients presenting to a referral hospital in southern Papua over an 8-year period. The hemoglobin level (an indicator of anemia) was measured in about a quarter of hospital presentations (some patients attended the hospital several times). A third of the presentations who had their hemoglobin level determined (67,696 presentations) had clinical malaria. Patients with P. malariae infection had the lowest average hemoglobin concentration. Patients with mixed species, P. falciparum, and P. vivax infections had slightly higher average hemoglobin levels but all these levels were below the normal range for people living in Papua. Among the patients who had their hemoglobin status assessed, 3.7% had severe anemia. After allowing for other factors that alter the risk of anemia (“confounding” factors such as age), patients with mixed Plasmodium infection were more than three times as likely to have severe anemia as patients without malaria. Patients with P. falciparum, P. vivax, or P. malariae infections were about twice as likely to have severe anemia as patients without malaria. About 12.2% of severe anemia was attributable to non-falciparum infections, 15.1% was attributable to P. falciparum monoinfections, and P. vivax was the dominant cause of severe anemia in infancy. Finally, compared to patients without anemia, patients with severe anemia had nearly a 6-fold higher risk of death.
What Do These Findings Mean?
These findings provide a comparative assessment of the pattern of anemia associated with non-falciparum malarias in Papua and an estimate of the public health importance of these malarias. Although the accuracy of these findings may be affected by residual confounding (for example, the researchers did not consider nutritional status when calculating how much malaria infection increases the risk of anemia) and other limitations of the study design, non-falciparum malarias clearly make a major contribution to the burden of anemia in southern Papua. In particular, these findings reveal the large contribution that P. vivax makes to severe anemia in infancy, show that the hematological (blood-related) impact of P. malariae is most apparent in adulthood, and suggest, in contrast to some previous reports, that mixed P. vivax/P. falciparum infection is associated with a higher risk of severe anemia than monoinfection with either species. These findings, which need to be confirmed in other settings, highlight the public health importance of implementing integrated malaria control strategies that aim to control all Plasmodium species rather than a single species in regions of Plasmodium co-endemicity.
Additional Information
Please access these websites via the online version of this summary at
This study is further discussed in a PLOS Medicine Perspective by Gosling and Hsiang
Information is available from the World Health Organization on malaria (in several languages); the 2012 World Malaria Report provides details of the current global malaria situation
The US Centers for Disease Control and Prevention provide information on malaria (in English and Spanish), including information on different Plasmodium species and a selection of personal stories about malaria
The Malaria Vaccine Initiative has fact sheets on Plasmodium falciparum malaria and on Plasmodium vivax malaria
MedlinePlus provides links to additional information on malaria and on anemia (in English and Spanish)
Information is available from the WorldWide Antimalarial Resistance Network on antimalarial drug resistance for P. falciparum and P. vivax
PMCID: PMC3866090  PMID: 24358031
19.  Anemia and Associated Factors Among Pregnant Women Attending Antenatal Care Clinic in Wolayita Sodo Town, Southern Ethiopia 
Anemia during pregnancy is a common problem which affects both the mother's and her child's health. The main aim of the study was to determine the prevalence and associated risk factors of anemia among pregnant women.
We conducted a facility based cross-sectional study on 363 pregnant women attending antenatal care clinic in Wolayita Soddo Otona Hospital from January to March 2014. Sociodemographic data were collected through questionnaire based interview. Four milliliter of venous blood and five grams of fecal samples were collected from each pregnant woman. Hematological parameters were determined using CELL DYN 1800® (Abott, USA) Hematology analyzer. Stool samples were checked for intestinal parasites using both direct wet mount and formol-ether concentration techniques.
Data were analyzed using SPSS version 20 software.
Overall, the prevalence of anemia was 39.94% (95% CI: 34.7 – 45.2%), of which the majority (60%) had moderate anemia. The mean hemoglobin concentration was 11.55±2.97 g/dl. Age 15–24 years (AOR: 9.89, 95%CI:2.68–21.41), family size >5 (AOR:7.74, 95%CI:4.15–16.47), multigravida (AOR:2.66, 95%CI:1.1.31–4.53), having low income (AOR:5.81, 95%CI:2.93–14.11), current clinical illness (AOR: 6.38, 95%CI:3.13–13.00), intestinal parasitic infection (AOR:2.41, 95%CI:1.08–5.81), no history of contraceptive usage (AOR:5.02 95%CI:2.21–11.47), being in third trimesters (AOR:11.37, 95%CI:4.56–24.82), history of excess menstrual bleeding (AOR:9.82, 95%CI:3.27–21.35) and low body mass index (AOR:9.44, 95%CI:7.79–22.18) were identified as independent predictors of anemia among pregnant women.
Anemia prevalence was found out to be moderate public health importance. Identified risk factors should be considered for prevention and control of anemia among pregnant women.
PMCID: PMC4478267  PMID: 26124623
Hemoglobin; Anemia; Pregnant women; Antenatal care clinic
20.  Determinants of anemia in postpartum HIV-negative women in Dar es Salaam, Tanzania 
The determinants of anemia during both pregnancy and postpartum recovery remain incompletely understood in sub-Saharan African women.
In a prospective cohort study among pregnant women, we assessed dietary, biochemical, anthropometric, infectious and sociodemographic factors at baseline. In multivariate Cox proportional hazards models, we examined predictors of incident anemia (hemoglobin <11 g/dl) and iron deficiency anemia (anemia plus mean corpuscular volume <80 fL), and recovery from anemia and iron deficiency anemia through 18 months postpartum at antenatal clinics in Dar es Salaam, Tanzania between 2001 and 2005. A total of 2364 non-anemic pregnant women and 4884 anemic women were enrolled between 12 and 27 weeks of gestation.
In total, 292 women developed anemia during the postpartum period and 165 developed iron deficiency anemia, whereas 2982 recovered from baseline anemia and 2044 from iron deficiency anemia. Risk factors for postpartum anemia were delivery complications (RR 1.6, 95% confidence interval (CI) 1.13, 2.22) and low postpartum CD4 cell count (RR 1.73, 95% CI 0.96, 3.17). Iron/folate supplementation during pregnancy had a protective relationship with the incidence of iron deficiency anemia. Absence of delivery complications, education status and iron/folate supplementation were positively associated with time to recovery from iron deficiency.
Maternal nutritional status during pregnancy, prenatal iron/folate supplementation, perinatal care, and prevention and management of infections, such as malaria, are modifiable risk factors for the occurrence of, and recovery from, anemia.
PMCID: PMC3775569  PMID: 23612515
anemia; postpartum; iron deficiency; pregnancy
21.  Magnitude of Anemia and Associated Risk Factors among Pregnant Women Attending Antenatal Care in Shalla Woreda, West Arsi Zone, Oromia Region, Ethiopia 
Anemia during pregnancy is a common problem in developing countries and affects both the mother's and her child's health. The main objective of this study was to determine the prevalence of and the factors associated with anemia among pregnant women.
Facility based cross-sectional study design was conducted from June to August, 2011 on 374 pregnant women. Mothers who came for ANC during the study period and who met the inclusion criteria were interviewed and a capillary blood sample was taken. Hemoglobin level was determined by using HemoCue photometer, and interviewer administered questionnaire was used to collect data. Data were cleaned, coded and fed into SPSS version 16.0 for analysis.
The mean hemoglobin concentration was 12.05±1.5 g/dl and prevalence of anemia was 36.6%. Family sizes (COR=2.67, CI (1.65, 4.32), third trimester (COR=1.45, CI (1.11, 2.23), meat consumption <1x/wk (COR=3.47, CI (1.58, 7.64) and pica (COR=2.33, CI (1.52, 3.58) were significantly associated with anemia. Having five or more children (AOR=5.2, CI [1.29, 21.09]), intake of vegetables and fruits less than once per day (AOR= 6.7, CI [2.49, 17.89]), intake of tea always after meal (AOR = 12.83.CI [45-28.9]), and recurrence of illness during pregnancy (AOR=7.3, CI [2.12–25.39]) were factors associated with anemia.
This study showed that anemia is a moderate public health problem. Less frequent meat and vegetable consumption, parity ≥5 are risk factors for anemia. Therefore, reducing parity, taking balanced diet and use of mosquito nets during pregnancy are recommended.
PMCID: PMC3742894  PMID: 23950633
Hemoglobin; Anemia; Pregnancy; ANC
22.  Prevalence and severity of anemia among school children in Jimma Town, Southwest Ethiopia 
BMC Hematology  2014;14:3.
Anemia is a major health problem worldwide. Because of health and socioeconomic problems, the prevalence of anemia is higher in developing countries. Children and pregnant women are the most vulnerable groups to anemia. The aim of the present study was to determine the magnitude of anemia among school children.
A cross-sectional household survey was conducted in January 2011 on 423 children, aged 6–14 years, selected through systematic random sampling method. Sociodemographic and anthropometric data were collected using a pre-tested questionnaire. Capillary blood was taken from the fingertip of each child and hemoglobin was measured using HaemoCue digital photometer. All the necessary safety measures were taken during blood collection. Anthropometric indicators were measured using WHO’s guideline. Data analysis was made using SPSS Version 16.0 for Windows. The association between predictors and outcome variables were measured by a stepwise logistic regression model. Ethical permission was obtained; consent of the parents/guardian was taken and confidentiality was maintained.
A total of 404 children were studied. The mean age was 10.21(SD ± 1.89) years. The proportion of females was 217(53.7%). The mean hemoglobin level for both sexes was 11.59(SD ± 1.97 g/dl). The current prevalence of anemia was 152(37.6%), out of which, 73(18.1%) had mild while 79(19.6%) of them had moderate anemia. The prevalence of anemia among the age group of 6–11 years was 118(40.5%) while the prevalence among the group of 12–14 years old children was 34(30.1%). Among the selected variables in the logistic regression analysis, low family income [OR = 4.925, 95% CI(1.063,22.820)], mothers’ education [OR = 4.621, 95% CI(1.383,15.439)], intake of plant food [OR = 3.847, 95% CI(2.068, 7.157)] and intake of animal food [OR = 2.37, 95% CI(1.040,5.402)] were significantly and independently associated with anemia.
Anemia is a moderate public health problem in the study area. Family income, educational status of parents and inadequate plant and animal food intake are the predictors of anemia. Improving the economic status of the family, women education and health education about balanced animal and plant food consumption are recommended strategies to reduce the burden of anemia.
PMCID: PMC3896819  PMID: 24433408
Hemoglobin; Anemia; School children; Prevalence
23.  Association of maternal anemia with other risk factors in occurrence of Great obstetrical syndromes at university clinics, Kinshasa, DR Congo 
Maternal anemia, a common situation in developing countries, provokes impairment of nutrients/oxygen supply to the placenta-fetus unit that leads to Great obstetrical syndromes (GOS). In our setting, however, occurrence of GOS has been found also depending on variables existing prior to pregnancy such as diabetes in family, hypertension in family, previous macrosomia, stillbirth, SGA and pre-eclampsia as well as overweight/obesity. Our study thus aimed to determine the magnitude of maternal anemia and its association with these pre-pregnancy high-risk variables in occurrence of GOS.
This is a cross-sectional study including women delivered at the University Clinics of Kinshasa, DR Congo, 12. during 18 months. Anemia was stated at hemoglobin blood concentration < 10 g/dL. Sampled women were checked for pregnancy high-risk factors and pregnancy complications. Odds ratios (95 % confidence intervals) were calculated to establish associations of anemia with various variables. Multivariate calculations aimed to isolate variables influencing these associations. The p <0.05 was considered significant.
The study sample included 412 women, among whom 220 (53.4 %) were diagnosed anemic. Anemia was found significantly linked to malaria, urinary infection, cesarean section, prematurity, SGA and stillbirth whose risk was 1.6 – 6.1 times augmented. Anemia was also found linked to pre-pregnancy high-risk factors such as age < 18 and ≥ 35 years, previous miscarriage, grand multiparity, diabetes in family, previous prematurity, overweight/obesity, previous cesarean section and previous pre-eclampsia, all of them enhancing the link of maternal anemia with complications.
Maternal anemia is very prevalent among pregnant women of our setting. It strongly contributes to worsening of morbidities that act with pregnancy high-risk factors in raising the risk of cesarean section, prematurity, SGA and stillbirth.
PMCID: PMC4546213  PMID: 26292718
24.  Mapping the Risk of Anaemia in Preschool-Age Children: The Contribution of Malnutrition, Malaria, and Helminth Infections in West Africa 
PLoS Medicine  2011;8(6):e1000438.
Ricardo Soares Magalhães and colleagues used national cross-sectional household-based demographic health surveys to map the distribution of anemia risk in preschool children in Burkina Faso, Ghana, and Mali.
Childhood anaemia is considered a severe public health problem in most countries of sub-Saharan Africa. We investigated the geographical distribution of prevalence of anaemia and mean haemoglobin concentration (Hb) in children aged 1–4 y (preschool children) in West Africa. The aim was to estimate the geographical risk profile of anaemia accounting for malnutrition, malaria, and helminth infections, the risk of anaemia attributable to these factors, and the number of anaemia cases in preschool children for 2011.
Methods and Findings
National cross-sectional household-based demographic health surveys were conducted in 7,147 children aged 1–4 y in Burkina Faso, Ghana, and Mali in 2003–2006. Bayesian geostatistical models were developed to predict the geographical distribution of mean Hb and anaemia risk, adjusting for the nutritional status of preschool children, the location of their residence, predicted Plasmodium falciparum parasite rate in the 2- to 10-y age group (Pf PR2–10), and predicted prevalence of Schistosoma haematobium and hookworm infections. In the four countries, prevalence of mild, moderate, and severe anaemia was 21%, 66%, and 13% in Burkina Faso; 28%, 65%, and 7% in Ghana, and 26%, 62%, and 12% in Mali. The mean Hb was lowest in Burkina Faso (89 g/l), in males (93 g/l), and for children 1–2 y (88 g/l). In West Africa, severe malnutrition, Pf PR2–10, and biological synergisms between S. haematobium and hookworm infections were significantly associated with anaemia risk; an estimated 36.8%, 14.9%, 3.7%, 4.2%, and 0.9% of anaemia cases could be averted by treating malnutrition, malaria, S. haematobium infections, hookworm infections, and S. haematobium/hookworm coinfections, respectively. A large spatial cluster of low mean Hb (<80 g/l) and maximal risk of anaemia (>95%) was predicted for an area shared by Burkina Faso and Mali. We estimate that in 2011, approximately 6.7 million children aged 1–4 y are anaemic in the three study countries.
By mapping the distribution of anaemia risk in preschool children adjusted for malnutrition and parasitic infections, we provide a means to identify the geographical limits of anaemia burden and the contribution that malnutrition and parasites make to anaemia. Spatial targeting of ancillary micronutrient supplementation and control of other anaemia causes, such as malaria and helminth infection, can contribute to efficiently reducing the burden of anaemia in preschool children in Africa.
Please see later in the article for the Editors' Summary
Editors' Summary
Global estimates for the time period 1993–2005 suggest that that worldwide, nearly 300 million children had anemia, that is, hemoglobin levels less than 110 g/l. In sub-Saharan Africa, two-thirds of all children were anemic, representing 83.5 million children. These statistics are important because anemia in infancy and childhood is associated with poor cognitive development, reduced growth, problems with immune function—and ultimately, decreased survival. Malnutrition (including micronutrient deficiency, especially of iron, vitamin A, vitamin C, and folate), undernutrition, and infectious diseases, particularly HIV, malaria, and helminth infections (caused by hookworm and Schistosoma haematobium—which causes urinary schistosomiasis), are major causes of anemia in children. Although iron supplementation can often correct anemia, in some circumstances, iron deficiency can protect against common infectious agents, and giving iron can, on occasion, increase the severity of infectious disease in some children. Focusing on the treatment and prevention of infectious diseases that cause anemia is therefore an important alternative strategy in the treatment of anemia.
Why Was This Study Done?
Control tools for targeting interventions for malaria and helminth infection in sub-Saharan Africa include modern spatial risk prediction methods that combine statistical models with geographical information systems (similar to those used in car navigation systems). However, to date no studies have used these tools to spatially predict the risk of anemia. Furthermore, the contribution that malnutrition and infections make to the overall anemia burden in Africa is largely unknown. In this study the researchers used these tools to predict the prevalence of anemia in three West African countries and to estimate the attributable risk of anemia due to malnutrition, malaria, and helminth infections.
What Did the Researchers Do and Find?
The researchers used geographically linked data from the most recent Demographic and Health Surveys (DHS) in Burkina Faso (2003), Ghana (2003), and Mali (2006), which included capillary blood sampling and testing and detailed anthropometric (height and weight) measurements. A total of 7,147 children aged 1–4 years (3,477 girls and 3,670 boys) in the three countries were included in the analysis. The researchers mapped DHS survey locations in the three study countries using DHS cluster coordinates in a geographic information system. Using data from the Malaria Atlas Project, the researchers extracted spatially predicted values of Plasmodium falciparum parasite rate for each DHS cluster using a geographical information system and used previously reported parasitological survey data of hookworm and S. haematobium infections to predict helminth infection risk across the region. Then the researchers developed spatial prediction models using Bayesian statistics to estimate of the population attributable fraction for specific predictors for anemia. Data from the DHS showed that the prevalence of mild, moderate, and severe anemia was 21%, 66%, and 13% in Burkina Faso; 28%, 65%, and 7% in Ghana, and 26%, 62%, and 12% in Mali. The prevalence of stunting, wasting, and being underweight in the study area was 87.8%, 89.7%, and 71.2%, respectively, and the mean P. falciparum parasite rate, and rates of S. haematobium infection, hookworm infection, and S. haematobium/hookworm coinfection for the study area were 52.0%, 26.8%, 8.2%, and 3.6%, respectively. The overall results indicate that in the three countries, approximately 6.7 million children aged 1–4 years have anemia. Severe malnutrition, P. falciparum infection, hookworm infection, S. haematobium infection, and hookworm/S. haematobium coinfection were responsible for an estimated 2.5 million, 1.0 million, 250,000, 285,000, and 61,000 anemia cases, respectively. Central Burkina Faso and southern Ghana had the highest number of anemic children.
What Do These Findings Mean?
These results add insight and detail to anemia prevalence and anemia severity within different geographical areas in three West African countries. The combination of anemia and mean hemoglobin predictive maps identifies communities in West Africa where preschool-age children are at increased risk of morbidity. The use of anemia maps has important practical implications for targeted control in these countries, such as guiding the efficient allocation of nutrient supplements and fortified foods, and enabling risk assessment of anemia due to different causes, which would in turn constitute an evidence base to calculate the best balance between interventions.
Additional Information
Please access these Web sites via the online version of this summary at
This study is further discussed in a PLoS Medicine Perspective by Abdisalan Noor
The WHO Web site has comprehensive information on the worldwide prevalence of anemia
More information on Demographic Health Surveys is available
More information on global predictions of malaria is available
PMCID: PMC3110251  PMID: 21687688
25.  Determinants of postpartum anemia among women from a rural population in southern India 
Even though the problem of anemia during pregnancy has been adequately emphasized, very little attention has been paid to postpartum anemia. The objective of the current study was to estimate the mean change in maternal hemoglobin from 36 weeks’ gestation to 6 weeks postpartum and to identify the factors associated with anemia during the postpartum period among women in a rural development block in Tamil Nadu, India.
Ninety-three pregnant women were interviewed using a structured questionnaire at 36 weeks’ gestation and then at 2 and 6 weeks postpartum. Blood samples were collected from the participants at 36 weeks’ gestation and at 6 weeks postpartum. Paired t-tests assessing the difference in mean hemoglobin prepartum and postpartum, univariate analysis, and multiple logistic regression to identify factors associated with postpartum anemia were done using Statistical Package for the Social Sciences version 12 for Microsoft Windows software.
The proportion of study subjects who were anemic (hemoglobin <11 g/dL) at 36 weeks’ gestation was 26.8% and at 6 weeks postpartum was 47.3% (hemoglobin <12 g/dL). The mean hemoglobin at 36–38 weeks’ gestation was 11.70±1.43 g/dL and at 6 weeks postpartum was 12.10±1.27 g/dL. Anemia at 36 weeks’ gestation (odds ratio [OR] 10.47, 95% confidence interval [CI] 2.37–42.34), heavy blood loss perceived by the mother during delivery (OR 12.91, 95% CI 2.01–61.25), younger maternal age (<21 years, OR 2.45, 95% CI 1.28–23.86), and inadequate iron supplementation during the postpartum period (OR 3.53, 95% CI 1.18–11.37) were identified as significant factors associated with anemia at 6 weeks postpartum.
Anemia during the third trimester of pregnancy, heavy bleeding perceived by the mother during delivery, younger maternal age, and inadequate iron supplementation during the postpartum period were associated with postpartum anemia.
PMCID: PMC3990363  PMID: 24748821
anemia; hemoglobin; iron deficiency; postpartum

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