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
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
Objectives. To determine rate and factors associated with small-for-gestational-age (SGA) births to women with HIV. Methods. Prospective data were collected from 183 pregnant women with HIV in an urban HIV prenatal clinic, 2000–2011. An SGA birth was defined as less than the 10th or 3rd percentile of birth weight distribution based upon cut points developed using national vital record data. Bivariate analysis utilized chi-squared and t-tests, and multiple logistic regression analyses were used. Results. The prevalence of SGA was 31.2% at the 10th and 12.6% at the 3rd percentile. SGA at the 10th (OR 2.77; 95% CI, 1.28–5.97) and 3rd (OR 3.64; 95% CI, 1.12–11.76) percentiles was associated with cigarette smoking. Women with CD4 count >200 cells/mm3 at the first prenatal visit were less likely to have an SGA birth at the 3rd percentile (OR 0.29; 95% CI, 0.10–0.86). Women taking NNRTI were less likely to have an SGA infant at the 10th (OR 0.28; 95% CI, 0.10–0.75) and 3rd (OR 0.16; 95% CI, 0.03–0.91) percentiles compared to those women on PIs. Conclusions. In this cohort with high rates of SGA, severity of HIV disease, not ART, was associated with SGA births after adjusting for sociodemographic, medication, and disease severity.
To examine the Institute of Medicine (IOM) guidelines for gestational weight gain in adolescents.
Retrospective cohort using the Missouri Birth Certificate Registry. Included subjects were primiparous, singleton gestations, <20 years, delivered 24–44 weeks gestation. The exposure was defined as weight gain less than, within, or greater than IOM recommendations. Outcomes examined were small-for-gestational-age infants (SGA), large-for-gestational age infants (LGA), preterm delivery, infant death, preeclampsia, cesarean delivery, and operative vaginal delivery. The analysis was stratified by body mass index (BMI) category.
In any BMI category, inadequate weight gain was associated with increased odds of SGA, preterm delivery and infant death. When subjects gained more than IOM recommendations, SGA decreased with slight increases in LGA, preeclampsia, and cesarean delivery.
Adolescents should be counseled regarding adequate weight gain in pregnancy. Further research is necessary to determine if the IOM recommendations recommend enough weight gain in adolescents to optimize pregnancy outcomes.
Adolescent pregnancy; Gestational Weight Gain; body mass index
Evidence relating chronic hypertension to risk of small for gestational age (SGA) births is conflicting. To identify factors associated with SGA that may involve a placental pathogenesis, we related chronic hypertension and other maternal factors that may be markers of endothelial dysfunction to preterm compared with term SGA births.
Chronic hypertension, diabetes, body mass index, age, and subfertility were related to risk of term and preterm SGA births in the Danish National Birth Cohort (n=81,008). SGA births were those with a birth weight adjusted for gestational age greater than 2 standard deviations below the mean based on fetal growth curves.
Risk of preterm SGA increased 5.5-fold (95% CI 3.2-9.4) and risk of term SGA increased 1.5-fold (1.0-2.2) among women with definite chronic hypertension. Risk of preterm SGA but not term SGA was increased among women less than 20 (odds ratio [OR] 2.8, 95% CI: 1.1-6.8) or greater than 36 (OR 2.0 , 95% CI:1.3-3.1) years of age and among those with at least 2 early spontaneous abortions (OR 2.0, CI:1.3-3.3). Smoking, parity, time to pregnancy greater than 12 months, and underweight status were similarly related to term and preterm SGA. Overweight status, obesity, and presence of diabetes were unrelated to either SGA subtype.
Chronic hypertension, young or older maternal age, and recurrent early spontaneous abortions increased risk for preterm SGA. These factors may involve abnormal placentation and likely represent a pathogenesis distinct from that leading to term SGA.
Cigarette smoking protects against preeclampsia but increases the risk of small-for-gestational-age birth (SGA). Regarding body weight, the converse is true: obesity elevates rates of preeclampsia but reduces rates of SGA. The authors assessed the combined effects of smoking and weight among US women developing preeclampsia or SGA, studying 7,757 healthy, primigravid women with singleton pregnancies in 1959–1965. Smoking (never, light, heavy), stratified by prepregnancy body mass index (BMI (weight (kg)/height (m)2); underweight, overweight, obese), was examined in relation to preeclampsia and SGA. Among underweight (BMI <18.5) and normal-weight (BMI 18.5–24.9) women, smoking decreased the risk of preeclampsia (for heavy smoking, light smoking, nonsmoking, test for trend p = 0.002 for underweight and p = 0.009 for normal weight) after adjustment for age, race, and socioeconomic status. However, among overweight/obese women (BMI ≥25), this trend was not apparent (p = 0.4). Among both underweight and overweight women, smoking significantly increased SGA risk (trend p < 0.001 for underweight and p = 0.02 for overweight/obese). Obesity eliminated the inverse association between smoking and preeclampsia but did not substantially alter the positive association between smoking and SGA. A possible unifying biologic explanation is discussed in this paper.
body weight; infant, small for gestational age; overweight; pre-eclampsia; pregnancy; smoking
Background: Perinatal stress is thought to underlie the Barker sequelae of low birth weight, of which precocious pubarche may be a manifestation.
Aims: To explore whether prematurity as well as smallness for gestational age (SGA) predisposes to precocious pubarche, and the potential role of excess weight gain during childhood.
Methods: Retrospective chart review of 89 children (79 girls) with precocious pubarche.
Results: Sixty five per cent were overweight/obese at diagnosis, compared with 19–24% of Australian children. Thirty five per cent had a history of SGA and 24% of prematurity. Weight SDS increased from birth to diagnosis in 91% of children. The mean change in weight SDS from birth to diagnosis was greater in those who were SGA (2.8, 95% CI 2.2 to 3.4) versus AGA (1.7, 95% CI 1.3 to 2.2), with no difference in the incidence of overweight/obesity. The latter was lower among children born premature (40% versus 72% term) but was associated with a mean increase in weight of 1.3 SDS during childhood. Nine out of ten girls and boys with precocious pubarche had at least one of the three risk factors studied.
Conclusions: Both prematurity and SGA were associated with precocious pubarche, as was overweight/obesity, irrespective of size or gestation at birth. Excess weight gain in childhood may predispose to precocious pubarche in susceptible individuals.
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.
Being born small for gestational age (SGA), a proxy for intrauterine growth restriction (IUGR) and prenatal famine exposure are both associated with a greater risk of metabolic disease. Both associations have been hypothesized to involve epigenetic mechanisms. We investigated whether prenatal growth restriction early in pregnancy was associated with changes in DNA methylation at loci that were previously shown to be sensitive to early gestational famine exposure. We compared 38 individuals born preterm (<32 weeks) and with a birth weight too low for their gestational age (less than −1SDS; SGA) with 75 individuals born preterm but with a birth weight appropriate for their gestational age (greater than −1SDS) and a normal postnatal growth (greater than −1SDS at three months post term; AGA). The SGA individuals were not only lighter at birth, but also had a smaller length (p = 3.3 × 10−13) and head circumference at birth (p = 4.1 × 10−13). The DNA methylation levels of IGF2, GNASAS, INSIGF and LEP were 48.5, 47.5, 79.4 and 25.7% respectively. This was not significantly different between SGA and AGA individuals. Risk factors for being born SGA, including preeclampsia and maternal smoking, were also not associated with DNA methylation at these loci. Growth restriction early in development is not associated with DNA methylation at loci shown to be affected by prenatal famine exposure. Our and previous results by others indicate that prenatal growth restriction and famine exposure may be associated with different epigenetic changes or non-epigenetic mechanisms that may lead to similar later health outcomes.
SGA; DOHAD; IUGR; DNA methylation; famine; IGF2; LEP; INS; GNASAS
The obesity epidemic raises concerns about the impact of excessive and insufficient weight gain during pregnancy.
We examined the association between gestational weight gain (GWG) and preterm birth, term small- and large-for-gestational-age (SGA and LGA), term birthweight, and term primary Cesarean delivery, considering prepregnancy body mass index (BMI) and ethnicity in a cohort of 33,872 New York City residents who gave birth between 1995 and 2003 and delivered in hospitals elsewhere in New York State.
Preterm birth (<37 weeks’ gestation) showed a modest U-shaped relationship, with projected GWG of <10 kg and 20+ kg associated with odds ratios of 1.4 and 1.3, respectively, relative to 10 to 14 kg. The pattern was stronger for preterm birth <32 weeks’ and for underweight women with low GWG and overweight/obese women with high GWG. Term SGA decreased and term LGA and birthweight increased monotonically with increasing GWG. Primary Cesarean delivery followed the same pattern as LGA, but less strongly.
Although the study is limited by potential selection bias and measurement error, our findings support the contention that GWG may be a modifiable predictor of pregnancy outcome that warrants further investigation, particularly randomized trials, to assess whether the relation is causal.
Birth Weight; Cesarean Delivery; Fetal Growth Retardation; Fetal Macrosomia; Infant; Small-for-Gestational Age; Premature Birth; Weight Gain
Children born small-for-gestational-age (SGA) are at increased risk of developing obesity and metabolic diseases later in life, a risk which is magnified if followed by accelerated postnatal growth. We investigated whether common gene variants associated with adult obesity were associated with increased postnatal growth, as measured by BMI z-score, in children born SGA and appropriate for gestational age (AGA) in the Auckland Birthweight Collaborative.
A total of 37 candidate SNPs were genotyped on 547 European children (228 SGA and 319 AGA). Repeated measures of BMI (z-score) were used for assessing obesity status, and results were corrected for multiple testing using the false discovery rate.
SGA children had a lower BMI z-score than non-SGA children at assessment age 3.5, 7 and 11 years. We confirmed 27 variants within 14 obesity risk genes to be individually associated with increasing early childhood BMI, predominantly in those born AGA.
Genetic risk variants are less important in influencing early childhood BMI in those born SGA than in those born AGA, suggesting that non-genetic or environmental factors may be more important in influencing childhood BMI in those born SGA.
BMI; Childhood obesity; AGA children; SGA children
Improved survival due to advances in neonatal care has brought issues such as postnatal growth and development more to the focus of our attention. Most studies report stunting in children born very preterm and/or small for gestational age. In this article we study the growth pattern of these children and aim to identify factors associated with postnatal catch-up growth.
1338 children born with a gestational age <32 weeks and/or a birth weight of <1500 grams were followed during a Dutch nationwide prospective study (POPS). Subgroups were classified as appropriate for gestational age and <32 weeks (AGA) or small for gestational age (<32 wks SGA and ≥32 wks SGA). Data were collected at different intervals from birth until 10 years for the 962 survivors and compared to reference values. The correlation between several factors and growth was analysed.
At 10 years the AGA children had attained normal height, whereas the SGA group demonstrated stunting, even after correction for target height (AGA: 0.0 SDS; SGA <32 wks: -0.29SDS and ≥32 wks: -0.13SDS). Catch-up growth was especially seen in the SGA children with a fast initial weight gain. BMI was approximately 1 SD below the population reference mean.
At 10 years of age, children born very preterm AGA show no stunting. However, many children born SGA, especially the very preterm, show persistent stunting. Early weight gain seems an important prognostic factor in predicting childhood growth.
Socioeconomic status (SES) is adversely associated with perinatal outcomes. This association is likely to be mediated by tobacco exposure. However, previous studies were limited to single perinatal outcomes and devoted no attention to environmental tobacco exposure. Therefore, this study aimed firstly to explain the role of maternal smoking in the association between maternal education and preterm birth (PTB), low birth weight (LBW) and small for gestational age (SGA), and secondly to explain whether environmental tobacco smoke mediates these associations further.
This study was nested in a population-based cohort study in the Netherlands, the Amsterdam Born Children and their Development (ABCD) study. Analyses were done in a sample of 3821 pregnant women of Dutch origin, using logistic regression analysis.
Least educated women, who were more often smoking and exposed to environmental tobacco smoke, had a significantly higher risk of PTB (OR 1.95 [95% CI: 1.19–3.20]), LBW (OR 2.41 [95% CI: 1.36–4.27]) and SGA (OR 1.90 [95% CI 1.32–2.74]) than highly educated women. The mediating effect of smoking in the least educated women was 43% for PTB, 55% for LBW and 66% for SGA. Environmental tobacco smoke did not explain these associations further. After adjustment for maternal smoking, the association between lower maternal education and pregnancy outcomes was no longer significant.
Smoking explains to a considerable extent the association between lower maternal education and adverse perinatal outcomes. Therefore, tobacco-interventions in lower educated women should be primarily focussed on maternal smoking to reduce PTB, LBW, and SGA. Additional attention to environmental tobacco exposure does not seem to reduce educational inequalities in perinatal outcomes.
Cigarette smoking protects against preeclampsia but increases the risk for small-for-gestational age (SGA). For body weight, the converse is true: obesity elevates rates of preeclampsia but reduces rates of SGA. We assessed the combined effects of smoking and weight among women developing preeclampsia or SGA.
We studied 7757 healthy, primigravid women with singleton pregnancies. Smoking (never, light, heavy), stratified by pre-pregnancy body mass index (BMI: underweight, overweight, obese) was examined in relation to preeclampsia and SGA.
Among underweight (BMI <18.5 kg/m2) and normal weight (BMI 18.5−24.9) women, smoking decreased the risk for preeclampsia (test for trend for heavy smoking, light smoking, non-smoking p=0.002 for underweight and p=0.009 for normal weight), after adjustment for age, race, and socioeconomic status. But among overweight/obese women (BMI ≥ 25), this trend was not apparent (p=0.4). Among both underweight and overweight women, smoking significantly increased SGA (trend p<0.001 for underweight and p=0.02 for overweight/obese).
Obesity eliminated the inverse association between smoking and preeclampsia but did not substantially alter the positive association between smoking and SGA. A possible unifying biologic explanation is discussed.
smoking; overweight; preeclampsia; growth restriction; pregnancy
To examine the importance of maternal weight characteristics as predictors of overweight (BMI ≥85th percentile and <95th percentile) and obesity (BMI ≥ 95th percentile) in offspring at age 4 years.
Chi-square and logistic regression analyses were conducted on a sample of 321 mother/child pairs from an earlier observational cohort study on mothers’ postpartum weight retention.
Maternal early pregnancy BMI and infant birth weight were each positively and significantly (p <0.05) associated with increased risk of obesity in offspring at age 4 years. A significant interaction was found between these two variables in predicting children’s risk of obesity. It was driven by the high proportion of obese children among obese women who had infants weighing < 3 kg at birth. Net gestational weight gain was not associated with obesity risk in children, but was positively associated with infant birth weight among normal weight and overweight women.
Reducing maternal BMI in the preconception period among overweight and obese women and preventing excessive weight gain in pregnancy for all women appear to be appropriate strategies to address the childhood obesity epidemic.
Being born small for gestational age (SGA) is associated with decreased insulin sensitivity and increased blood pressure in childhood, but the association with clinical disease in early adulthood is less certain. The Danish Medical Birth Registry has registered all births in Denmark since 1973, but due to variable data quality, data is most often used only from 1981 onwards, and birth registers in other countries may have similar problems for the early years. We wanted to examine whether the data can be used for identification of children born SGA and used in future research.
All persons born between 1974 and 1996 were identified in the Danish Medical Birth Registry (n = 1.704.890). Immigrants and children without data on gestational age and birth weight were excluded, and a total of 1.348.106 children were included in the analysis. The difference between the different variables used in the history of the registry were examined, and the quality of data in the birth registry from 1974-1981 was examined and compared to subsequent years.
Data on birth weight and gestational age in the early years of the registry is inconsistent, and the identification of children born SGA is inaccurate, with 49% false-positives. The biggest source of error is due to the rough and inaccurate intervals used for gestational age. By using –3 standard deviations as a cut-off for the identification of children born SGA, the number of false-positives was reduced to 9%, while the amount of false-negatives were increased.
Choosing –3 standard deviations for identifying children born SGA is a viable, though not optimal solution for identifying children born SGA. Overall the data in the registry is of sufficient quality to be used in further medical research.
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.
Birth weight often is used to predict how preterm infants will grow, but scant attention has been paid to the effect of neonatal morbidities on growth trajectories. We investigated birth weight and neonatal morbidity in preterm infants' growth to age 12 years.
A five-group, prospective, longitudinal study was conducted with 194 infants: 46 full term; 29 healthy preterm without morbidity; 56 preterm with medical illness (MPT); 34 preterm with neurologic illness; and 29 preterm small for gestational age (SGA). Height, weight, and body mass index were measured at six ages.
The full-term group had greater height than the preterm groups to age 8 years, when healthy preterm and MPT groups caught up. Only the SGA group had smaller height at age 12 years. The MPT, preterm with neurologic illness, and SGA groups had lower weight through age 12 years. Body mass index was appropriate for preterm groups by age 4 years. Across time, neonatal morbidity had a significant effect on height and weight trajectories. Birth weight was significant for weight trajectories only.
With variation in growth trajectories, details of neonatal morbidity in health history interviews will inform child health assessments.
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.
Individuals born small for gestational age (SGA) are at increased risk of rapid postnatal weight gain, later obesity and diseases in adulthood such as type 2 diabetes, hypertension and cardiovascular diseases. Environmental risk factors for SGA are well established and include smoking, low pregnancy weight, maternal short stature, maternal diet, ethnic origin of mother and hypertension. However, in a large proportion of SGA, no underlying cause is evident, and these individuals may have a larger genetic contribution.
In this study we tested the association between SGA and polymorphisms in genes that have previously been associated with obesity and/or diabetes. We undertook analysis of 54 single nucleotide polymorphisms (SNPs) in 546 samples from the Auckland Birthweight Collaborative (ABC) study. 227 children were born small for gestational age (SGA) and 319 were appropriate for gestational age (AGA).
Results and Conclusion
The results demonstrated that genetic variation in KCNJ11, BDNF, PFKP, PTER and SEC16B were associated with SGA and support the concept that genetic factors associated with obesity and/or type 2 diabetes are more prevalent in those born SGA compared to those born AGA. We have previously determined that environmental factors are associated with differences in birthweight in the ABC study and now we have demonstrated a significant genetic contribution, suggesting that the interaction between genetics and the environment are important.
To examine the association between narrowly defined subsets of maternal ethnicity and birth outcomes.
Analysis of 1995-2003 New York City birth certificates linked to hospital discharge data for 949,210 singleton births to examine the multivariable associations between maternal ethnicity and preterm birth, subsets of spontaneous and medically indicated preterm birth, term small for gestational age (SGA), and term birthweight.
Compared to non-Hispanic whites, Puerto Ricans had an elevated odds ratio (OR 1.9, 95% CI 1.9-2.0) for delivering at 32-36 weeks (adjusted for nativity, maternal age, parity, education, tobacco use, pre-pregnancy weight, birth year). We found an excess of adverse outcomes among most Latino groups. Outcomes also varied within regions, with North African infants nearly 100g (adjusted) heavier than sub-Saharan Africans.
The considerable heterogeneity in risk of adverse perinatal outcomes is obscured in broad categorizations of maternal race/ethnicity, and may help to formulate etiologic hypotheses.
Ethnic groups; Epidemiology; Outcomes; pregnancy
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
Atrazine and other corn herbicides are routinely detected in drinking water. Two studies on potential association of atrazine with small-for-gestational-age (SGA) and preterm birth prevalence found inconsistent results. Moreover, these studies did not control for individual-level potential confounders.
Our retrospective cohort study evaluated whether atrazine in drinking water is associated with increased prevalence of SGA and preterm birth.
We developed atrazine concentration time series for 19 water systems in Indiana from 1993 to 2007 and selected all births (n = 24,154) based on geocoded mother’s residences. Log-binomial models were used to estimate prevalence ratios (PRs) for SGA and preterm delivery in relation to atrazine concentrations during various periods of the pregnancy. Models controlled for maternal demographic characteristics, prenatal care and reproductive history, and behavioral risk factors (smoking, drinking, drug use).
Atrazine in drinking water during the third trimester and the entire pregnancy was associated with a significant increase in the prevalence of SGA. Atrazine in drinking water > 0.1 μg/L during the third trimester resulted in a 17–19% increase in the prevalence of SGA compared with the control group (< 0.1 μg/L). Mean atrazine concentrations over the entire pregnancy > 0.644 μg/L were associated with higher SGA prevalence than in the control group (adjusted PR = 1.14; 95% confidence interval, 1.03–1.24). No significant association was found for preterm delivery.
We found that atrazine, and perhaps other co-occurring herbicides in drinking water, is associated with an increased prevalence of SGA, but not preterm delivery.
atrazine; birth weight; epidemiology; herbicides; preterm birth
Objective. Retrospective single-centre analysis of growth characteristics in 182 healthy short children born small for gestational age (SGA) or appropriate for gestational age (idiopathic short stature, ISS). Methods. Birth size references from the USA and Sweden were compared, and for the classification as SGA or ISS the Swedish reference was chosen. Height, target height (TH), bone age (BA), predicted adult height (PAH), IGF-I and IGFBP-3 values were compared between SGA and ISS. Results. In the combined group, birth weight and length showed a symmetric Gaussian distribution. The American reference overestimates the percentage of short birth length and underestimates that of low birth weight. In childhood, SGA children were shorter than ISS (−3.1 versus −2.6 SDS, P < .001), also in comparison to TH (−2.6 versus −1.9 SDS, P < .001). TH, height SDS change over time, BA delay, and PAH were similar. IGF-I and IGFBP-3 were lower in ISS (P = .03 and .09). Conclusions. SGA children represent the left tail of the Gaussian distribution of birth size in short children. The distinction between SGA and ISS depends on birth size reference. Childhood height of SGA is lower than of ISS, but the other auxological features are similar.
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