We sought to determine the association between small for gestational age (SGA), birth weight, and childhood obesity within preterm polysubstance exposed children. We sampled 312 preterm children with 11-year body mass index (BMI; age- and sex-specific) data from the Maternal Lifestyle Study (51% girls, 21.5% SGA, 46% prenatal cocaine, and 55% tobacco exposed). Multinomial regression analyzed the association between 11-year obesity (OBE) and overweight (OW) and SGA, birth weight, first-year growth velocity, diet, and physical activity variables. Overall, 24% were OBE (BMI for age ≥95th percentile) and 16.7% were OW (BMI ≥85th and <95th percentiles). In adjusted analyses, SGA was associated with OW (odds ratio [OR]=3.4, confidence interval [CI] 1.5 to 7.5). Higher birth weight was associated with OBE (OR = 1.8, CI 1.3 to 2.4) and OW (OR=1.4, CI 1.1 to 2.0). Growth velocity was associated with OBE (OR=2.7, CI 1.8 to 4.0) and OW (OR=1.6, CI 1.1 to 2.4). Low exercise was associated with OBE (OR=2.1, CI 1.0 to 4.4) and OW (OR=2.1, CI 1.0 to 4.5). There was no effect of substance exposure on obesity outcomes. Many (41%) of these high-risk preterm 11-year-olds were obese/overweight. Multiple growth-related processes may be involved in obesity risk for preterm children, including fetal programming as indicated by the SGA effect.
Childhood obesity; premature birth; infant SGA; birth weight; exercise; prenatal drug exposure
Human immunodeficiency virus (HIV) is prevalent in many countries where small-for-gestational age (SGA) and premature delivery are also common. However, the associations between maternal HIV, preterm delivery and SGA infants remain unclear. We estimate the prevalence of SGA and preterm (<37 weeks) births, their associations with antenatal maternal HIV infection and their contribution to infant mortality, in a high HIV prevalent, rural area in South Africa.
Data were collected, in a non-randomized intervention cohort study, on all women attending antenatal clinics (2001–2004), before the availability of antiretroviral treatment. Newborns were weighed and gestational age was determined (based on last menstrual period plus midwife assessment antenatally). Poisson regression with robust variance assessed risk factors for preterm and SGA birth, while Cox regression assessed infant mortality and associated factors.
Of 2368 live born singletons, 16.6% were SGA and 21.4% were preterm. HIV-infected women (n= 1189) more commonly had SGA infants than uninfected women (18.1 versus 15.1%; P = 0.051), but percentages preterm were similar (21.8 versus 20.9%; P = 0.621). After adjustment for water source, delivery place, parity and maternal height, the SGA risk in HIV-infected women was higher [adjusted relative risk (aRR) 1.28, 95% confidence interval (CI): 1.06–1.53], but the association between maternal HIV infection and preterm delivery remained weak and not significant (aRR: 1.07, 95% CI: 0.91–1.26). In multivariable analyses, mortality under 1 year of age was significantly higher in SGA and severely SGA than in appropriate-for-gestational-age infants [adjusted hazard ratio (aHR): 2.12, 95% CI: 1.18–3.81 and 2.77, 95% CI: 1.56–4.91], but no difference in infant mortality was observed between the preterm and term infants (aHR: 1.18 95% CI: 0.79–1.79 for 34–36 weeks and 1.31, 95% CI: 0.58–2.94 for <34 weeks).
Maternal HIV infection increases the risk of SGA, but not preterm births, in this cohort.
HIV; SGA; preterm; Africa; low birthweight
Smoking during pregnancy is strongly associated with increased risk of small for gestational age (SGA) and low birth weight, while elevated prepregnancy body mass index (BMI) is associated with a decreased risk of SGA and higher birth weight. We investigated the combined effect of prenatal smoking and prepregnancy BMI on risk of SGA and on birth weight.
A total of 34,928 singleton, term pregnancies in residents of New York City between 1995 and 2003 were evaluated in multivariable regression models of birth weight and risk of SGA.
Increasing prepregnancy BMI reduced the risk of SGA and increased birth weight. The effect of prenatal smoking on birth weight and SGA diminished in women as their prepregnancy BMI increased, such that prenatal smoking did not significantly impact the risk of SGA among women who were overweight or obese prior to pregnancy. Prenatal smoking decreased mean birth weight by 187 grams (95% confidence interval (CI): -337, -37) among underweight women, by 129 grams (95% CI: -170, -87) among normal weight women, by 46 grams (95% CI: -113, +20) among overweight women, and by 75 grams (95% CI: -162, +11) among obese women.
This study suggests that the effect of smoking during pregnancy on SGA and birth weight is present in underweight and normal weight women but markedly reduced among obese and overweight women.
birth weight; body mass index; cigarette smoking; fetal growth retardation; infant; small for gestational age
Small for gestational age (SGA) infants comprise up to 50% of all stillbirths and a minority are detected before birth. We aimed to develop and validate early pregnancy predictive models for SGA infants.
5628 participants from SCOPE, a prospective study of nulliparous pregnant women, were interviewed at 15±1 weeks’ gestation. Fetal anthropometry, uterine and umbilical Doppler studies were performed at 20±1 weeks’. The cohort was divided into training (n = 3735) and validation datasets (n = 1871). All-SGA (birthweight <10th customised centile), Normotensive-SGA (SGA with normotensive mother) and Hypertensive-SGA (SGA with mother who developed hypertension) were the primary outcomes. Multivariable analysis was performed using stepwise logistic regression firstly using clinical variables and then with clinical and ultrasound variables. Receiver operator curves were constructed and areas under the curve (AUC) calculated.
633 infants (11.3%) in the whole cohort were SGA; 465 (8.3%) Normotensive-SGA and 165 (3.0%) Hypertensive-SGA. In the training dataset risk factors for All-SGA at 15±1 weeks’ included: family history of coronary heart disease, maternal birthweight <3000 g and 3000 g to 3499 g compared with ≥3500 g, >12 months to conceive, university student, cigarette smoking, proteinuria, daily vigorous exercise and diastolic blood pressure ≥80. Recreational walking ≥4 times weekly, rhesus negative blood group and increasing random glucose were protective. AUC for clinical risk factors was 0.63. Fetal abdominal or head circumference z scores <10th centile and increasing uterine artery Doppler resistance at 20±1 weeks’ were associated with increased risk. Addition of these parameters increased the AUC to 0.69. Clinical predictors of Normotensive and Hypertensive-SGA were sub-groups of All-SGA predictors and were quite different. The combined clinical and ultrasound AUC for Normotensive and Hypertensive-SGA were 0.69 and 0.82 respectively.
Predictors for SGA of relevance to clinical practice were identified. The identity and predictive potential differed in normotensive women and those who developed hypertension.
The objective of this study was to assess whether women who do not take multinutrient supplements during early pregnancy are more susceptible to the effects of low-to-moderate alcohol consumption on preterm birth and small-for-gestational-age birth (SGA) compared to women who do take multinutrients. This analysis included 800 singleton live births to mothers from a cohort of pregnant women recruited for a population-based cohort study conducted in the Kaiser Permanente Medical Care Program in Northern California. Participants were recruited in their first trimester of pregnancy and information about their alcohol use and supplement intake during pregnancy was collected. Preterm birth (n = 53, 7%) was defined as a delivery prior to 37 completed weeks of gestation and SGA birth (n = 124, 16%) was defined as birth weight less than the 10th percentile for the infant’s gestational age and sex compared to US singleton live births. A twofold increase in the odds of SGA birth attributed to low-to-moderate alcohol intake was found among multinutrient supplement non-users (95% CI: 1.1, 5.3). Yet, among multinutrient supplement users, there was no increased risk of an SGA birth for women who drank low-to-moderately compared to women who abstained (aOR: 0.97, 95% CI: 0.6, 1.6). Similar results emerged for preterm birth. Our findings provide marginal evidence that multinutrient supplementation during early pregnancy may modify the risk of SGA births and preterm birth associated with alcohol consumption during pregnancy and may have important implications for pregnant women and women of child-bearing age. However, future research needs to be conducted.
Low-to-moderate alcohol use; Multinutrient supplement use; Preterm birth; SGA birth; Multivitamin use
Objective. Small for gestational age (SGA) is associated with increased neonatal morbidity and mortality. At present, evidence on whether these pregnancies should be managed expectantly or by induction is lacking. To get insight in current policy we analysed data of the National Dutch Perinatal Registry (PRN).
Methods. We used data of all nulliparae between 2000 and 2005 with a singleton in cephalic presentation beyond 36+0 weeks, with a birth weight below the 10th percentile. We analysed two groups of pregnancies: (I) with isolated SGA and (II) with both SGA and hypertensive disorders. Onset of labour was related to route of delivery and neonatal outcome.
Results. Induction was associated with a higher risk of emergency caesarean section (CS), without improvement in neonatal outcome. For women with isolated SGA the relative risk of emergency CS after induction was 2.3 (95% Confidence Interval [CI] 2.1 to 2.5) and for women with both SGA and hypertensive disorders the relative risk was 2.7 (95% CI 2.3 to 3.1).
Conclusion. Induction in pregnancies complicated by SGA at term is associated with a higher risk of instrumental deliveries without improvement of neonatal outcome. Prospective studies are needed to determine the best strategy in suspected IUGR at term.
Interferon (IFN)-γ inducible protein, CXCL10/IP-10, is a member of the CXC chemokine family with pro-inflammatory and anti-angiogenic properties. This chemokine has been proposed to be a key link between inflammation and angiogenesis. The aim of this study was to determine whether preeclampsia and delivery of a small for gestational age (SGA) neonate are associated with changes in maternal serum concentration of CXCL10/IP-10.
This cross-sectional study included patients in the following groups: (1) non pregnant women (N=49); (2) women with normal pregnancies (N=89); (3) patients with preeclampsia (N=100); and (4) patients who delivered an SGA neonate (N=78). SGA was defined as birth weight below the 10th percentile. Maternal serum concentrations of CXCL10/IP-10 were measured by sensitive immunoassay. Non-parametric statistics were used for analysis.
(1) Patients with normal pregnancies had a significantly higher median serum concentration of CXCL10/IP-10 than non-pregnant women (median: 116.1 pg/mL, range: 40.7-1314.3 vs. median: 90.3 pg/mL, range: 49.2-214.7, respectively; p=0.002); (2) no significant correlation was found between maternal serum concentration of CXCL10/IP-10 and gestational age (between 19 and 38 weeks); (3) there were no differences in median serum CXCL10/IP-10 concentrations between patients who delivered an SGA neonate and those with normal pregnancies (median: 122.4 pg/mL, range: 37.3-693.5 vs. median: 116.1 pg/mL, range: 40.7-1314.3, respectively; p>0.05); (4) patients with preeclampsia had a higher median serum concentration of CXCL10/IP-10 than normal pregnant women (median: 156.4 pg/mL, range: 47.4-645.9 vs. median: 116.1 pg/mL, range: 40.7-1314.3, respectively; p<0.05); (5) patients with preeclampsia had a higher median concentration of CXCL10/IP-10 than those who delivered an SGA neonate (median: 156.4 pg/mL, range: 47.4-645.9 vs. median: 122.4 pg/mL, range: 37.3-693.5, respectively; p<0.05).
Patients with preeclampsia have significantly higher serum concentrations of CXCL10/IP-10 than both normal pregnant women and mothers who have SGA neonates. These results are likely to reflect an anti-angiogenic state as well as an enhanced systemic inflammatory response in patients with preeclampsia. Alternatively, since preeclampsia and SGA share several mechanisms of disease, it is possible that a higher concentration of this chemokine may contribute to the clinical presentation of preeclampsia in patients with a similar intrauterine insult.
Pregnancy; CXCL10; IP-10; chemokine; chemotactic cytokine; small for gestational age; SGA; angiogenesis
To evaluate the impact of prenatal cocaine exposure and small-for-gestational-age (SGA) status on childhood growth.
Cocaine exposure was defined by history or meconium metabolites. Hierarchical linear modeling was used to examine cocaine exposure and SGA status on growth, while controlling for exposure to other drugs and alcohol use.
At birth cocaine-exposed infants (n=364) had significantly lower growth parameters compared to non-exposed children (n=771). At 6 years, weight was similar between exposed and unexposed children. SGA infants continued to be growth impaired. There was a significant interaction between prenatal cocaine exposure and SGA status at 6 years. The negative effects of cocaine on weight and height were greater among non-SGA than SGA children (432 vs. 280 gm, and 0.7 and 0.5 cm, respectively) while negative effects of SGA status on weight and height were larger in non-cocaine exposed compared to the exposed children (2.3 kg vs.1.6 kg and 2.2 and 1.0 cm).
Children exposed to prenatal cocaine were similar in weight to non-exposed children at 6 years of age. Cocaine had an unexplained greater detrimental effect on non-SGA than SGA children. SGA status at birth has an independent detrimental effect on childhood growth.
Prenatal cocaine exposure; small for gestational age; childhood growth
The authors examined whether early ultrasound dating (≤20 weeks) of gestational age (GA) in small-for-gestational-age (SGA) fetuses may underestimate gestational duration and therefore the incidence of SGA birth. Within a population-based case-control study (May 2002–June 2005) of Iowa SGA births and preterm deliveries identified from birth records (n = 2,709), the authors illustrate a novel methodological approach with which to assess and correct for systematic underestimation of GA by early ultrasound in women with suspected SGA fetuses. After restricting the analysis to subjects with first-trimester prenatal care, a nonmissing date of the last menstrual period (LMP), and early ultrasound (n = 1,135), SGA subjects’ ultrasound GA was 5.5 days less than their LMP GA, on average. Multivariable linear regression was conducted to determine the extent to which ultrasound GA predicted LMP dating and to correct for systematic misclassification that results after applying standard guidelines to adjudicate differences in these measures. In the unadjusted model, SGA subjects required a correction of +1.5 weeks to the ultrasound estimate. With adjustment for maternal age, smoking, and first-trimester vaginal bleeding, standard guidelines for adjudicating differences in ultrasound and LMP dating underestimated SGA birth by 12.9% and overestimated preterm delivery by 8.7%. This methodological approach can be applied by researchers using different study populations in similar research contexts.
bias (epidemiology); gestational age; infant, small for gestational age; pregnancy; premature birth; ultra-sonography
Higher risks of preterm birth and small for gestational age babies have been reported in teenagers. The aim of this study was to investigate the relationship between first and second teenage pregnancies and preterm birth, birthweight and small for gestational age (SGA).
All women aged 14 to 29 yrs who gave birth to live singletons in the North Western Region of England between January 1st 2004 and December 31st 2006 were identified. Women were classified in three groups; 14-17 yrs, 18-19 yrs and 20-29 yrs (reference group). The outcome measures were preterm birth, very preterm birth, birthweight, SGA (< 5th percentile), very SGA (VSGA< 3rd percentile). We compared these outcome measures in teenagers' first and second pregnancies with those of mothers aged 20 to 29 yrs.
The risk of preterm birth was increased in first (OR = 1.21, [95% CI: 1.01-1.45]) and second (OR = 1.93, [95% CI: 1.38-2.69]) time mothers aged 14-17 yrs compared to the reference group. Birthweight was reduced in the first (mean difference = -24 g; [95% CI: -40, -7]) and second (mean difference = -80 g; [95% CI: -115, -46]) time mothers aged 14-17 yrs compared to the reference group. There was some evidence of a protective effect against VSGA in 14-17 yr old first time mothers (OR = 0.79, [95% CI: 0.63-0.99]).
Teenage mothers are at increased risk of preterm birth compared to adult mothers and this risk is further increased in second time teen pregnancies. This study highlights the importance of ensuring pregnant teenagers have appropriate antenatal care. A first pregnancy may be the first and only time a pregnant teenager interacts with health services and this opportunity for health education and the promotion of contraception should not be overlooked.
Although evidence suggests that some occupations may be a risk factor for small-for-gestational age (SGA) birth, associations between a wide range of maternal and paternal occupations and risk of SGA births remain unclear. Our objective was to analyze the risk of SGA births by parental occupation, including the entire Swedish population of mothers (≥20 years) and fathers.
We linked nationwide data (1990–2004) on singletons born to employed mothers to nationwide data on maternal and paternal occupation and other individual-level variables. Information on parental occupations was obtained from the 1990 census. Approximately 95% of SGA births (calculated using normative data) were defined on the basis of ultrasound. Odds ratios of SGA birth were calculated with 95% confidence intervals. Women and men were analyzed separately.
There were 816 310 first singleton live births during the study period, of which 29 603 were SGA events. Families with low incomes had an increased risk of SGA births. After accounting for maternal age at the infant's birth, period of birth, family income, region of residence, marital status and smoking habits, several maternal occupational groups (including ‘mechanics and iron and metalware workers’ and ‘packers, loaders and warehouse workers’) had a significantly higher risk of SGA birth than the reference group (all women in the study population). Among paternal occupational groups, only waiters had an increased risk of SGA birth.
This large-scale follow-up study shows that maternal occupation affects risk of SGA birth, whereas paternal occupation does not seem to have an impact on SGA birth. Further studies are required to examine the specific agents in those maternal occupations that are associated with an increased risk of SGA birth.
family income; follow-up study; occupational exposure; small for gestational age
Being small-for-gestational-age (SGA) is associated with an increased risk of morbidity, but questions remain about how best to diagnose SGA, and thus, predict poor health consequences. The authors sought to compare an individualized reference for defining SGA with a simple ultrasound reference in predicting poor cognitive development at age five.
The authors used data from the Successive SGA Births Study, a prospective study including 699 Alabaman and 618 Scandinavian women recruited from 1986 to 1988, and whose children had cognitive development scores measured at age five. Sensitivity, specificity and positive predictive value (PPV) were estimated for each reference using cognitive development as the benchmark. Relative risk of poor neurodevelopment was calculated, comparing infants classified as SGA by either reference with infants not classified as SGA.
The individualized reference had higher sensitivity and PPV in predicting poor neurodevelopment. Babies defined as SGA by the individualized reference alone had a higher risk (RR=2.20, 95% CI: 1.20, 4.00) of poor cognitive outcome, while those identified by the ultrasound reference alone did not (RR=0.95, 95% CI: 0.45, 2.01). None of the references could predict poor neurodevelopment well at age five.
The individualized birthweight reference modestly outperforms the simple ultrasound reference in identifying SGA infants with poor child neurodevelopment. However, neither reference can predict child neurodevelopment well.
Birth Weight; Fetal Development; Infant; Small for Gestational Age; Wechsler Scales
In adults, the TCF7L2 rs7903146 T allele, commonly associated with type 2 diabetes (T2D), has been also associated with a lower body mass index (BMI) in T2D individuals and with a smaller waist circumference in subjects with impaired glucose tolerance.
The present association study aimed at analyzing the contribution of the rs7903146 SNP to smallness for gestational age (SGA) and metabolic profiles in subjects with SGA or appropriate for gestational age birth weight (AGA). Two groups of French Caucasian subjects were selected on birth data: SGA (birth weight < 10th percentile; n = 764), and AGA (25th < birth weight < 75th percentile; n = 627). Family-based association tests were also performed in 3,012 subjects from 628 SGA and AGA pedigrees.
The rs7903146 genotypic distributions between AGA (30.7%) and SGA (29.0%) were not statistically different (allelic OR = 0.92 [0.78–1.09], p = 0.34). Family association-based studies did not show a distortion of T allele transmission in SGA subjects (p = 0.52). No significant effect of the T allele was detected on any of the metabolic parameters in the SGA group. However, in the AGA group, trends towards a lower insulin secretion (p = 0.03) and a higher fasting glycaemia (p = 0.002) were detected in carriers of the T allele.
The TCF7L2 rs7903146 variant neither increases the risk for SGA nor modulates birth weight and young adulthood glucose homeostasis in French Caucasian subjects born with SGA.
The individualized reference for defining small for gestational age (SGA) at birth has gained popularity in recent years. However, its utility on fetal assessment has not been evaluated. The authors compare an individualized with an ultrasound reference in predicting poor perinatal outcomes. Data from a large clinical trial in predominantly white US women (1987–1991) with singleton pregnancies (n = 9,526) were used. The individualized reference classified fewer SGA fetuses than the ultrasound reference, but the risks of adverse outcomes were similar between fetuses classified by both references. The risk increased substantially only when the percentiles fell below the 5th percentile (likelihood ratio positive at birth = 2.68 (95% confidence interval (CI): 2.00, 3.58) and 3.13 (95% CI: 2.34, 4.18) for ultrasound and individualized references, respectively). SGA fetuses defined by either the individualized or ultrasound reference alone had risk ratios of adverse outcomes of 1.91 (95% CI: 0.77, 4.77) and 1.18 (95% CI: 0.37, 3.77), respectively, compared with normal fetuses (the difference between these 2 risk ratios, P = 0.71). The authors conclude that neither the ultrasound-based nor the individualized reference does well in predicting adverse perinatal outcomes. The 5th percentile may be a better cutpoint than the 10th percentile in defining SGA.
fetal growth retardation; infant, small for gestational age; perinatal mortality
The outcomes of small for gestational age (SGA) infants especially in extremely low birth weight infants (ELBWIs) are controversial. This study evaluated the mortality and morbidity of ELBWIs, focusing on whether or not they were also SGA.
The medical records of 415 ELBWIs (birth weight <1,000 g), who were inborn and admitted to the Samsung Medical Center neonatal intensive care unit from January 2000 to December 2008, were reviewed retrospectively. Mortality and morbidities were compared by body size groups: very SGA (VSGA), birth weight ≤3rd percentile; SGA, 3rd to 10th percentile; and appropriate for gestational age (AGA) infants, >10th percentile for gestational age. For gestational subgroup analysis, groups were divided into infants with gestational age ≤24+6 weeks (subgroup I), 25+0 to 26+6 weeks (subgroup II), and ≥27+0 weeks (subgroup III).
Gestational age was 29+2±2+6 weeks in the VSGA infants (n=49), 27+5±2+2 weeks in the SGA infants (n=45), and 25+4±1+4 weeks in AGA infants (n=321). Birth weight was 692±186.6 g, 768±132.9 g, and 780±142.5 g in the VSGA, SGA, and AGA groups, respectively. Cesarean section rate and maternal pregnancy-induced hypertension were more common in the VSGA and SGA than in AGA pregnancies. However, chorioamnionitis was more common in the AGA group. The mortalities of the lowest gestational group (subgroup I), and also of the lower gestational group (subgroup I+II) were significantly higher in the VSGA group than the SGA or AGA groups (P=0.020 and P=0.012, respectively). VSGA and SGA infants showed lower incidence in respiratory distress syndrome, ductal ligation, bronchopulmonary dysplasia, intraventricular hemorrhage than AGA group did. However, by multiple logistic regression analysis of each gestational subgroup, the differences were not significant.
Of ELBWIs, extremely SGA in the lower gestational subgroups, had an impact on mortality, which may provide information useful for prenatal counseling.
Small for gestational age; Extremely low birth weight infants; Mortality; Morbidity
The study is a descriptive, population-based analysis of birth outcomes in the New York State Finger Lakes region designed to determine whether perinatal outcomes differed across 3 rural typologies.
Hospital birth data for the Finger Lakes region from 2006-2007 were used to identify births classified as low birthweight (LBW), small for gestational age (SGA), and preterm delivery (PTD). Maternal residences were defined using 3 existing zip-code-level rural-urban typologies: Census Bureau zip codes, Rural-Urban Commuting Area codes, and Primary Service Areas. Within each typology, rural maternal characteristics and birth outcomes were compared to those in urban areas using multivariable logistic regression models.
In bivariate analyses, rurality was associated with LBW and SGA for all typologies, while PTD was associated with residence in the Census Bureau typology only. After controlling for demographic characteristics, births to mothers in the most rural level of the Census Bureau typology and to all rural mothers in the RUCA and Primary Service Area typologies were more likely to be LBW and PTD. SGA was not consistently associated with residence across typologies.
The typologies produced similar results for these outcomes, although effects were of greater magnitude in the RUCA and Primary Service Area typologies than in the Census Bureau typology. Comparison across typologies can have practical implications for researchers and policy makers interested in understanding the dynamics of rurality and birth outcomes in their regions.
birth outcomes; regression analysis; residence characteristics; rural
To estimate the association between pre-pregnancy body mass index (BMI) and small for gestational age (SGA) neonates, and to determine if there is a synergistic effect of tobacco use on SGA across all BMI strata.
Retrospective cohort study of 65,104 patients seen for second-trimester ultrasound. BMI was categorized into underweight, normal weight, overweight, and obese. SGA was defined as birth weight <10th percentile and <5th percentile. Univariable and multivariable logistic regression analyses were used to evaluate the association between BMI and SGA. Stratified analyses and tests for effect modification were performed to evaluate for a potential synergistic effect between tobacco use and abnormal pre-pregnancy BMI on SGA.
After controlling for potential confounders, underweight BMI was significantly associated with an increased risk for SGA <10th percentile (aOR 1.8, 95% CI 1.5–2.1) while overweight (aOR 0.7, 95% CI 0.7–0.8) and obese BMI (aOR 0.6, 95% CI 0.5–0.7) were associated with a decreased risk of SGA. There was no effect modification of tobacco use on the risk of SGA across all BMI categories.
While both tobacco and underweight BMI are independently associated with SGA, there was no evidence of synergism. Continued emphasis on both smoking cessation and maintenance of normal pre-pregnancy BMI remain paramount to decreasing the incidence of SGA.
body mass index; tobacco; small for gestational age; underweight
We sought to evaluate the risk of intrauterine fetal death (IUFD) in small-for-gestational-age (SGA) fetuses.
We analyzed a retrospective cohort of all births in the United States in 2005, as recorded in a national database. We calculated the risk of IUFD within 3 sets of SGA threshold categories as well as within non-SGA pregnancies using the number of at-risk fetuses as the denominator.
The risk of IUFD increased with gestational age and was inversely proportional to percentile of birthweight for gestational age. The risk for IUFD in those <3rd percentile was as high as 58.0 IUFDs per 10,000 at-risk fetuses, 43.9 for <5th percentile, and 26.3 for <10th percentile compared to 5.1 for non-SGA gestations.
There is an increase in the risk of IUFD in SGA fetuses compared to non-SGA fetuses at all gestational ages with the greatest risk demonstrated in the lowest percentile cohort evaluated.
birthweight; fetal death; small for gestational age; stillbirth
the effects of small for gestational age (SGA) in very low birthweight
(VLBW) infants on growth and development until the fifth year of life.
METHODS—VLBW (< 1500
g) infants, selected from a prospective study, were classified as SGA
(n = 115) on the basis of birth weight below the 10th percentile for
gestational age and were compared with two groups of appropriate for
gestational age (AGA) infants matched according to birth weight
(AGA-BW; n = 115) or gestation at birth (AGA-GA; n = 115).
Prenatal, perinatal, and postnatal risk factors were recorded, and
duration and intensity of treatment were computed from daily
assessments. Body weight, length, and head circumference were measured
at birth, five and 20 months (corrected for prematurity), and at 56 months. General development was assessed at five and 20 months with the
Griffiths scale of babies abilities, and cognitive development at 56 months with the Columbia mental maturity scales, a vocabulary (AWST)
and language comprehension test (LSVTA).
group differences were found in complications (pregnancy, birth, and
neonatal), parity, and multiple birth rate. The AGA-GA group showed most satisfactory growth up to 56 months, with both the AGA-BW and SGA groups lagging behind. The AGA-GA group also scored significantly more highly on all developmental and
cognitive tests than the other groups. Developmental test results were
similar for the SGA and AGA-BW groups at five and 20 months, but AGA-BW
infants (lowest gestation) had lower scores on performance intelligence
quotient and language comprehension at 56 months than the SGA group.
When prenatal and neonatal complications, parity, and multiple birth
were accounted for, group differences in growth remained, but
differences in cognitive outcome disappeared after five months.
underweight and with a short gestation (SGA and VLBW) leads to poor
weight gain and head growth in infancy but does not result in poorer
growth than in infants of the same birth weight but shorter gestation
(AGA-BW) in the long term. SGA is related to early developmental delay
and later language problems; however, neonatal complications may have a
larger detrimental effect on long term cognitive development of VLBW
infants than whether they are born SGA or AGA.
Ireland introduced a comprehensive workplace smoke-free legislation in March, 2004. Smoking-related adverse birth outcomes have both health care and societal cost implications. The main aim of this study was to determine the impact of the Irish smoke-free legislation on small-for-gestationa- age (SGA) births.
Methods and Findings
We developed a population-based birthweight (BW) percentile curve based on a recent study to compute SGA (BW <5th percentile) and very SGA (vSGA - BW<3rd percentile) for each gestational week. Monthly births born between January 1999 and December 2008 were analyzed linking with monthly maternal smoking rates from a large referral maternity university hospital. We ran individual control and CUSUM charts, with bootstrap simulations, to pinpoint the breakpoint for the impact of ban implementation ( = April 2004). Monthly SGA rates (%) before and after April 2004 was considered pre and post ban period births, respectively. Autocorrelation was tested using Durbin Watson (DW) statistic. Mixed models using a random intercept and a fixed effect were employed using SAS (v 9.2). A total of 588,997 singleton live-births born between January 1999 and December 2008 were analyzed. vSGA and SGA monthly rates declined from an average of 4.7% to 4.3% and from 6.9% to 6.6% before and after April 2004, respectively. No auto-correlation was detected (DW = ∼2). Adjusted mixed models indicated a significant decline in both vSGA and SGA rates immediately after the ban [(−5.3%; 95% CI −5.43% to −5.17%, p<0.0001) and (−0.45%; 95% CI: −0.7% to −0.19%, p<0.0007)], respectively. Significant gradual effects continued post the ban periods for vSGA and SGA rates, namely, −0.6% (p<0.0001) and −0.02% (p<0.0001), respectively.
A significant reduction in small-for-gestational birth rates both immediately and sustained over the post-ban period, reinforces the mounting evidence of the positive health effect of a successful comprehensive smoke-free legislation in a vulnerable population group as pregnant women.
Infants who are born small for gestational age (SGA) are at risk for developmental delays, which may be related to deficiencies in zinc, an essential trace metal, or to deficiencies in their ability to elicit caregiver responsiveness (functional isolation hypothesis). The objective of this study was to evaluate at 6 and 10 months of age the impact of a 9-month supplementation trial of 5 mg of zinc on the development and behavior of infants who were born SGA and to evaluate infants’ ability to elicit responsive caregiver behavior.
A randomized, controlled trial of zinc supplementation was conducted among 200 infants in a low-income, urban community in Delhi, India. Infants were recruited when they were full term (>36 weeks) and SGA (birth weight <10th percentile weight-for-gestational age). Infants were randomized to receive daily supplements of a micronutrient mix (folate, iron, calcium, phosphorus, and riboflavin) with or without 5 mg of zinc sulfate. The supplement was administered by field workers daily from 30 days to 9 months of age. At 6 and 10 months, infant development and behavior were measured in a clinical setting using the Bayley Scales of Infant Development II. Caregiver responsiveness, observed on an Indian version of the Home Observation for Measurement of the Environment scale, was measured during a home visit at 10 months. During both the clinic and home visits, caregivers reported on their infant’s temperament.
There were no direct effects of zinc supplementation on the infants’ development or behavior at either 6 or 10 months. In a subgroup analysis among the zinc-supplemented infants, lower birth weight infants were perceived to be more temperamentally difficult than higher weight infants; in the control group, birth weight was not associated with temperament. Heavier birth weight infants had better scores on all measures of development and behavior at 6 months and on changes in mental and motor development from 6 to 10 months, compared with lighter birth weight infants. Boys had better weight gain and higher scores on mental development and emotional regulation than girls. Infants who were from families of higher socioeconomic status (indexed by parental education, house size, and home ownership) had higher scores on mental development and orientation/engagement (exploratory behavior) than infants who were from families of lower socioeconomic status. In keeping with the functional isolation hypothesis, caregiver responsiveness was associated with infant irritability, controlling for socioeconomic status, gender, birth weight, and weight gain. Responsive mothers were more likely to perceive their infants to be temperamentally easy than less responsive mothers.
Possible explanations for the lack of effects of zinc supplementation on infant development and behavior include 1) subtle effects of zinc supplementation that may not have been detected by the Bayley Scales, 2) interference with other nutritional deficiencies, or 3) no impact of zinc deficiency on infants’ development and behavior. The link between birth weight and irritability among infants in the zinc supplementation group suggests that the response to zinc supplementation may differ by birth weight, with irritability occurring among the most vulnerable infants. Longer term follow-up studies among zinc-supplemented infants are needed to examine whether early supplementation leads to developmental or behavioral changes that have an impact on school-age performance. The relationship between infant irritability and low maternal responsiveness lends support to the functional isolation hypothesis and the importance of asking caregivers about infant temperament.
zinc deficiency; cognitive development; mental development; motor development; behavior; temperament; maternal responsiveness
Small for gestational age (SGA) infants are at increased risk of short- and long-term adverse outcomes.
Population-based case–control study using data derived from the Finnish Medical Birth Register for the years 1987–2010 (total population of singleton live births n = 1,390,165). The aim was to quantify the importance of risk factors for SGA and describe their contribution to socioeconomic status (SES) disparities in SGA by using logistic regression analysis.
Of all the singleton live births (n = 1,390,165), 3.1% (n = 42,702) were classified as SGA (defined as below 2 standard deviations of the sex-specific population reference mean for gestational age). The risk of SGA was 11 − 24% higher in the lower SES groups compared to the highest SES group. Smoking alone made the largest contribution, explaining 41.7 − 50.9% of SES disparities in SGA. The risk of SGA was 2.3-fold and 7% higher among women who smoked or had quit smoking during the first trimester of pregnancy (adjusted odds ratio (aOR) 2.34, 95% CI 2.28-2.42 and aOR 1.07, 95% CI 1.00 − 1.15, respectively) compared with the non-smokers.
SGA is substantially affected by SES. Smoking explained up to 50% of the difference in risk of SGA between high and low SES groups. Quitting smoking during the first trimester of pregnancy resulted in a 7% higher incidence of SGA comparable to that of non-smoking women. Thus, interventional attempts to reduce smoking during pregnancy might help to decrease the socioeconomic gradient of SGA.
The newborn classified as growth-restricted on birth weight curves, but not on fetal weight curves, is classified prenatally as small for gestational age (SGA), but postnatally as appropriate for gestational age (AGA).
To see (1) to what extent the neurodevelopmental outcomes at 24 months corrected age differed among three groups of infants (those identified as SGA based on birth weight curves (B-SGA), those identified as SGA based on fetal weight curves only (F-SGA), and the referent group of infants considered AGA, (2) if girls and boys were equally affected by growth restriction, and (3) to what extent neurosensory limitations influenced what we found.
Observational cohort of births before the 28 week of gestation. Outcome measures: Mental Development Index (MDI) and Psychomotor Development Index (PDI) of the Bayley Scales of Infant Development II.
B-SGA, but not F-SGA girls were at an increased risk of a PDI < 70 (OR=2.8; 95% CI: 1.5, 5.3) compared to AGA girls. B-SGA and F-SGA boys were not at greater risk of low developmental indices than AGA boys. Neurosensory limitations diminished associations among girls of B-SGA with low MDI, and among boys B-SGA and F-SGA with PDI < 70.
Only girls with the most severe growth restriction were at increased risk of neurodevelopmental impairment at 24 months corrected age in the total sample. Neurosensory limitations appear to interfere with assessing growth restriction effects in both girls and boys born preterm.
There are differences in the literature regarding outcomes of premature small-for-gestational-age (SGA) and appropriate-for gestational-age (AGA) infants, possibly due to failure to take into account gestational age at birth.
To compare mortality and respiratory morbidity of SGA and AGA premature newborn infants.
A retrospective study was done of the 2,487 infants born without congenital anomalies at ≤36 weeks of gestation and admitted to the neonatal intensive care unit (NICU) at John Dempsey Hospital, between Jan. 1992 and Dec. 1999. Recent (1994–96) U.S. birth weight percentiles for gestational age (GA), race and gender were used to classify neonates as SGA (<10th percentile for GA) or AGA (10th–90th percentile for GA). Using multivariate logistic regression and survival analyses to control for GA, SGA and AGA infants were compared for mortality and respiratory morbidity.
Controlling for GA, premature SGA infants were at a higher risk for mortality (Odds ratio 3.1, P = 0.001) and at lower risk of respiratory distress syndrome (OR = 0.71, p = 0.02) than AGA infants. However multivariate logistic regression modeling found that the odds of having respiratory distress syndrome (RDS) varied between SGA and AGA infants by GA. There was no change in RDS risk in SGA infants at GA ≤ 32 wk (OR = 1.27, 95% CI 0.32 – 1.98) but significantly decreased risk for RDS at GA > 32 wk (OR = 0.41, 95% CI 0.27 – 0.63; p < 0.01). After controlling for GA, SGA infants were observed to be at a significantly higher risk for developing chronic lung disease as compared to AGA infants (OR = 2.2, 95% CI = 1.2 – 3.9, P = 0.01). There was no significant difference between SGA and AGA infants in total days on ventilator. Among infants who survived, mean length of hospital stay was significantly higher in SGA infants born between 26–36 wks GA than AGA infants.
Premature SGA infants have significantly higher mortality, significantly higher risk of developing chronic lung disease and longer hospital stay as compared to premature AGA infants. Even the reduced risk of RDS in infants born at ≥32 wk GA, (conferred possibly by intra-uterine stress leading to accelerated lung maturation) appears to be of transient effect and is counterbalanced by adverse effects of poor intrauterine growth on long term pulmonary outcomes such as chronic lung disease.
Inconsistent data on the association between prenatal alcohol exposure and a range of pregnancy outcomes, such as preterm birth (PTB) and small for gestational age (SGA) raise new questions. This study aimed to assess whether the association between low-moderate prenatal alcohol exposure and PTB and SGA differs according to maternal education, maternal mental distress or maternal smoking.
The Amsterdam Born Children and their Development (ABCD) Study (N = 5,238) and the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) (N = 16,301) are both large studies. Women provide information on alcohol intake in early pregnancy, 3 months postpartum and up to 17 years retrospectively. Multivariate logistic regression analyses and stratified regression analyses were performed to examine the association between prenatal alcohol exposure and PTB and SGA, respectively.
No association was found between any level of prenatal alcohol exposure (non-daily, daily, non-abstaining) and SGA. The offspring of daily drinkers and non-abstainers had a lower risk of PTB [ABCD: odds ratio (OR) 0.31, 95% confidence interval (CI) 0.13, 0.77; KiGGS: OR 0.75, 95% CI 0.57, 0.99]. Interactions with maternal education, maternal distress or maternal smoking were not significant.
Although these results should be interpreted with caution, both studies showed no adverse effects of low-moderate prenatal alcohol exposure on PTB and SGA, not even in the offspring of women who were disadvantaged in terms of low education, high levels of distress, or smoking during pregnancy.
Prenatal alcohol exposure; Pregnancy outcomes; Maternal education; Distress; Smoking