Gestational Age-adjusted Birth Weight Research Articles

Birth outcomes following bictegravir exposure during pregnancy.

Bictegravir is increasingly prescribed as a co-formulated tablet with tenofovir alafenamide and emtricitabine to pregnant persons with HIV (PWH) despite limited pregnancy and birth outcome data. We sought to provide birth outcome data following exposure to bictegravir during pregnancy. We conducted a descriptive analysis of infants born to pregnant PWH 18-45 years of age enrolled in at least one Pediatric HIV/AIDS Cohort Study (PHACS)-affiliated study who received bictegravir for ≥7 days during pregnancy and completed follow-up through delivery. The outcomes of interest were gestational age at birth, preterm birth (<37 weeks' gestation), gestational-age adjusted birth weight (BWZ) and length (BLZ) z-scores, small for gestational age (SGA, birthweight <10th percentile), congenital anomalies, neonatal deaths in the first 28 days of life, and infant HIV status. A total of 177 infants born to 170 unique PWH were exposed to bictegravir for ≥7 days during gestation; 55% were exposed to bictegravir from the time of conception. Median gestational age at birth was 38.1 weeks. The prevalence of preterm birth was 15.8% and SGA was 9.3%. Mean BWZ and BLZ were -0.48 and 0.03. No neonatal deaths or perinatal HIV transmissions were reported. Among 126 infants exposed to first-trimester bictegravir, 7 (5.6%) had major congenital anomalies with no specific pattern suggestive of a syndrome. These findings provide preliminary data without significant safety concerns for fetal bictegravir exposure in this United States cohort. Comparative data and continued surveillance of outcomes among infants exposed to bictegravir during gestation are warranted.

Maternal blood pressure and birth weight associations in U.S.-born and foreign-born Latinas.

Research suggests that acculturating to the United States is detrimental for immigrants' health. Consistent with this pattern, higher levels of U.S. acculturation among Latina-American women have been associated with giving birth to lower birth weight babies. The mechanisms that shape this shift in pregnancy health are not clear, but researchers have begun to consider the role of physiological systems that are sensitive to social experience. The present study examined the association of cultural orientation with blood pressure (BP) trajectories over the course of pregnancy. In a study of 1,011 U.S.- and foreign-born Latina-American women, cultural orientation was assessed and multiple BP measures were collected throughout pregnancy. Postpregnancy data, including gestational age-adjusted birth weight, were extracted from medical records. Bayesian structural equation models examined average BP and slopes of BP change during pregnancy while accounting for psychosocial stress, support, and pregnancy health-related factors (e.g., maternal age, smoking). We found evidence that greater U.S. orientation was associated with higher diastolic blood pressure (DBP) and steeper increases in DBP, which was associated with less fetal growth. This is the first evidence that BP may mediate the association between cultural orientation and pregnancy outcomes in Latina-American women. These findings advance our understanding of the biopsychosocial pathways through which acculturation to the U.S. links with health. As scholars seek to better understand the influence of U.S. acculturation on health, focusing on the cardiovascular system and other physiological systems that are sensitive to social experience is warranted and likely to prove valuable. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Evidence that highly canalized fetal traits are sensitive to intergenerational effects of maternal developmental nutrition.

Maternal experiences before pregnancy predict birth outcomes, a key indicator of health trajectories, but the timing and pathways for these effects are poorly understood. Here we test the hypothesis that maternal pre-adult growth patterns predict pregnancy glucose and offspring fetal growth in Cebu, Philippines. Using multiple regression and path analysis, gestational age-adjusted birthweight and variables reflecting infancy, childhood, and post-childhood/adolescent weight gain (conditional weights) were used to predict pregnancy HbA1c and offspring birth outcomes among participants in the Cebu Longitudinal Health and Nutrition Survey. Maternal early/mid-childhood weight gain predicted birth weight, length, and head circumference in female offspring. Late-childhood/adolescent weight gain predicted birth length, birth weight, skinfold thickness, and head circumference in female offspring, and head circumference in male offspring. Pregnancy HbA1c did not mediate relationships between maternal growth and birth size parameters. In Cebu, maternal growth patterns throughout infancy, childhood, and adolescence predict fetal growth via a pathway independent of circulating glucose, with stronger impacts on female than male offspring, consistent with a role of developmental nutrition on offspring fetal growth. Notably, the strength of relationships followed a pattern opposite to what occurs in response to acute pregnancy stress, with strongest effects on head circumference and birth length and weakest on skinfolds. We speculate that developmental sensitivities are reversed for stable, long-term nutritional cues that reflect average local environments. These findings are relevant to public health and life-history theory as further evidence of developmental influences on health and resource allocation across the life course.

Influence of birth weight on later life cardiovascular structure, function and disease: unpacking influences from direct genetic effects versus intrauterine programming

Abstract Aims The cardinal risk factors for cardiovascular disease in adulthood are well-recognised. In addition to these, observational studies have suggested that intrauterine and early developmental factors might play a role. However, observational associations are liable to influence by residual confounding and bias. Additionally, observational and genetic studies to date have not been able to isolate the fetal versus maternal influences. Purpose We aim to explore the causal relevance of birth weight on cardiovascular disease and cardiac structure and function using Mendelian randomization (MR), and specifically investigate the role of fetal genetic effects (reflecting the direct causal influence of birth weight) versus maternal genetic effects (reflecting the influence of the intrauterine environment). Methods Uncorrelated (r2&amp;lt;0.001), genome-wide significant (p&amp;lt;5x10-8) SNPs were extracted from genome-wide association study summary statistics for gestational age-adjusted birth weight overall, and after isolating the indirect maternal versus direct fetal genetic effects. Inverse-variance weighted Mendelian randomisation (MR) was utilised for primary analyses on outcomes of atrial fibrillation, coronary artery disease, heart failure, ischaemic stroke, and 15 measures of cardiac structure and function indexed to body surface area. Multivariable MR was utilised to explore potential mediation of effects observed on cardiovascular outcomes by cardiometabolic risk factors. P-values were FDR-adjusted to account for multiple testing. Results Higher genetically-predicted birth weight was associated with higher risk of atrial fibrillation (OR 1.26 [1.15-1.39], p&amp;lt;0.001), but lower risk of coronary artery disease (OR 0/78 [0.71-0.86] p&amp;lt;0.001). These associations were driven predominantly by direct fetal genetic effects. For the association with atrial fibrillation, there was no evidence of mediation through body mass index or height. For the association with coronary artery disease, there was at least partial mediation through systolic blood pressure (Figure 1). Higher genetically-predicted birth weight was associated with a greater chamber volumes, but lower ejection fraction (Figure 2), driven by direct fetal genetic effects. Conclusion The results of this study suggest that lower birthweight is associated with higher risk of coronary artery disease, partly mediated by a higher systolic blood pressure. Conversely, a greater birth weight was associated with higher risk of atrial fibrillation, and this was not mediated by body mass index or height. Higher birth weight was also associated with greater chamber volumes and lower ejection fraction. The associations were in all cases predominantly driven by direct fetal effects, suggesting a causal relevance of birth weight itself, and not of the intrauterine environment, on later life cardiovascular disease.Figure 1Figure 2

Measuring the Effect of Neighborhood Racial Segregation on Fetal Growth.

Prior studies of neighborhood racial segregation and intrauterine growth have not accounted for confounding factors in early life. We used the Life-Course Influences on Fetal Environment Study of births to Black women in metropolitan Detroit, 2009-2011, (N = 1,408) to examine whether health and social conditions in childhood and adulthood confound or modify the association of neighborhood segregation (addresses during pregnancy geocoded to census tract racial composition) and gestational age-adjusted birthweight. Before adjusting for covariates, women living in a predominantly (≥75%) Black neighborhood gave birth to 47.3 grams (95% CI: -99.0, 4.4) lighter infants, on average, compared with women living in <75% Black neighborhoods. This association was confounded by adulthood (age at delivery, parity, neighborhood deprivation) and childhood (parental education, neighborhood racial composition) factors and modified by adulthood socioeconomic position. These findings underscore the complex relationship between neighborhood racial segregation and birth outcomes, which would be enhanced through a life course framework.

Identification of maternal continuous glucose monitoring metrics related to newborn birth weight in pregnant women with gestational diabetes.

To identify the specific glucose metrics derived from maternal continuous glucose monitoring (CGM) data, which were associated with a higher percentile of offspring birth weight. In this cohort study, we recruited singleton pregnant women with GDM who underwent CGM for 5-14 days at a mean of 28.8 gestational weeks between Jan 2017 and Nov 2018. Commonly used single summary glucose metrics of glucose exposure (including mean 24-h, daytime, and nighttime glucose level) and variability (including J-index and mean amplitude of glycaemic excursions) were derived from CGM data. A novel comprehensive glucose metric-hours per-day spent in a severe variability glucose mode (HSSV)-was identified using the spectral clustering method, which reflects both glucose level and variability. Multiple linear regression models were used to estimate the associations of sex- and gestational age-adjusted birth weight percentile with CGM parameters. Ninety-seven women comprising 127,279 glucose measurements were included. Each 1-SD increase in maternal nighttime mean glucose level and HSSV was associated with 6.0 (95% CI 0.4, 11.5) and 6.3 (95% CI 0.4, 12.2) percentage points increase in birth weight percentile, respectively. No associations were found between other glucose metrics and birth weight percentile. Nighttime mean glucose level has a comparable effect size to HSSV in association with fetal growth, suggesting that endogenous hyperglycemia might drive the association between maternal hyperglycemia and birth weight. Further studies need to examine the effect of lowering nighttime glucose level and/or HSSV on preventing fetal overgrowth in GDM women.

Common maternal and fetal genetic variants show expected polygenic effects on risk of small- or large-for-gestational-age (SGA or LGA), except in the smallest 3% of babies.

Babies born clinically Small- or Large-for-Gestational-Age (SGA or LGA; sex- and gestational age-adjusted birth weight (BW) <10th or >90th percentile, respectively), are at higher risks of complications. SGA and LGA include babies who have experienced environment-related growth-restriction or overgrowth, respectively, and babies who are heritably small or large. However, the relative proportions within each group are unclear. We assessed the extent to which common genetic variants underlying variation in birth weight influence the probability of being SGA or LGA. We calculated independent fetal and maternal genetic scores (GS) for BW in 11,951 babies and 5,182 mothers. These scores capture the direct fetal and indirect maternal (via intrauterine environment) genetic contributions to BW, respectively. We also calculated maternal fasting glucose (FG) and systolic blood pressure (SBP) GS. We tested associations between each GS and probability of SGA or LGA. For the BW GS, we used simulations to assess evidence of deviation from an expected polygenic model.Higher BW GS were strongly associated with lower odds of SGA and higher odds of LGA (ORfetal = 0.75 (0.71,0.80) and 1.32 (1.26,1.39); ORmaternal = 0.81 (0.75,0.88) and 1.17 (1.09,1.25), respectively per 1 decile higher GS). We found evidence that the smallest 3% of babies had a higher BW GS, on average, than expected from their observed birth weight (assuming an additive polygenic model: Pfetal = 0.014, Pmaternal = 0.062). Higher maternal SBP GS was associated with higher odds of SGA P = 0.005.We conclude that common genetic variants contribute to risk of SGA and LGA, but that additional factors become more important for risk of SGA in the smallest 3% of babies.

Birth outcomes are superior after transfer of fresh versus frozen embryos for donor oocyte recipients.

For donor oocyte recipients, are birth outcomes superior for fresh versus frozen embryos? Among fresh donor oocyte recipients, fresh embryos are associated with better birth outcomes when compared with frozen embryos. Frozen embryo transfer (ET) with vitrification has been associated with improved pregnancy rates, but also increased rates of large for gestational age infants. Donor oocyte recipients represent an attractive biological model to attempt to isolate the impact of embryo cryopreservation on IVF outcomes, yet there is a paucity of studies in this population. A retrospective cohort of the US national registry, the Society for Assisted Reproductive Technology Clinic Outcome Reporting System, of IVF cycles of women using fresh donor oocytes resulting in ET between 2013 and 2015. Thawed oocytes were excluded. Good obstetric outcome (GBO), defined as a singleton, term, live birth with appropriate for gestational age birth weight, was the primary outcome measure. Secondary outcomes included live birth, clinical pregnancy, spontaneous abortion, preterm birth, multiple births and gestational age-adjusted weight. Outcomes were modeled using the generalized estimating equation approach. Data are from 25387 donor oocyte cycles, in which 14289 were fresh and 11098 were frozen ETs. A GBO was 27% more likely in fresh ETs (26.3%) compared to frozen (20.9%) (adjusted risk ratio 1.27; 95% confidence interval (CI) 1.21-1.35; P < 0.001). Overall, fresh transfer was more likely to result in a live birth (55.7% versus 39.5%; adjusted risk ratio 1.21; 95% CI 1.18-1.26; P < 0.001). Among singleton births, there was no difference in gestational age-adjusted birth weight between groups. Our cohort findings contrast with data from autologous oocytes. Prospective studies with this population are warranted. Among donor oocyte recipients, fresh ETs may be associated with better birth outcomes. Reassuringly, given its prevalent use, modern embryo cryopreservation does not appear to result in phenotypically larger infants. None. N/A.

Gestational Triclosan Exposure and Infant Birth Weight: A Systematic Review and Meta-analysis

Background/Aim: Exposure to triclosan, an antimicrobial chemical used in personal care and cleaning products, has been associated with reduced birth weight in some, but not all studies. Thus, we conducted a systematic review and meta-analysis to characterize the relation of gestational triclosan exposure with infant birth weight, and identify potential sources of heterogeneity between studies. Methods: We identified original studies that measured maternal urinary triclosan concentrations during pregnancy and reported their association with infant birth weight. We considered birth weight, which we further characterized based on adjustment for gestational age or gestational age standardized birth weight z-scores. Using a random effects model, we estimated differences in these outcomes per 10-fold increase in triclosan concentrations. Results: Among thirteen identified studies, the range of median triclosan concentrations varied by approximately 2 orders of magnitude (0.6 to 29 ng/mL), with higher concentrations in North American and most European studies compared to Asian ones. Associations between triclosan and birth weight (β: -41g; 95% CI: -110, -28; n=4) were stronger than those when birth weight was adjusted for gestational age (β: -16g; 95% CI: -24, -8; n=8). Similarly, increasing triclosan was associated with modest decreases in birth weight z-scores (β: -0.08; 95% CI: -0.22, 0.07; n=4). The association between triclosan and gestational age adjusted birth weight was stronger in studies with higher median triclosan values &gt;10ng/mL compared to studies with median values &lt;10 ng/mL (β: -27g; 95% CI: -61, 7; n=3 vs. β: 6g; 95% CI: -20, 31; n=5). Conclusion: We observed that the association of urinary triclosan concentrations with birth weight varied by adjustment for gestational age and study-specific urinary triclosan concentrations. Our results suggest that urinary triclosan concentrations are associated with lower infant birth weight in populations with higher degrees of exposure prevalence.

Ambient ozone exposure during preconception and gestation periods and birth weight: when is the critical window?

Background: Prenatal exposure to ozone has been associated with lower birth weight. Yet few studies have included the preconception period. Moreover, the critical window of prenatal ozone exposure remains unclear. We aim to examine the association of ambient ozone exposure during preconception and gestation periods with birth weight, and to identify critical exposure windows.Methods: The study included 102 pregnant women at admission for delivery in Anzhen Hospital from July to December 2017 in Beijing, China. We collected information on participants’ demographics, health habits, residential address, and living environment. If participants worked before and/or during pregnancy, work addresses and duration at work on typical workdays were asked. Bi-weekly average ambient ozone levels were estimated for home and work addresses using a validated land use regression model. We weighted the time (hours) at home and work to estimate participants’ ozone exposure levels from 3 months before conception to the end of pregnancy. Birth weight, gestational age, sex, and maternal prenatal care history were extracted from medical records. We used distributed lag non-linear models to examine the association of monthly average ozone exposure with sex- and gestational age-adjusted birth weight z score and to identify critical exposure windows.Results: After adjusting for maternal age, pre-pregnancy body mass index, ethnicity, family income, and season of birth, two critical windows were identified: Birth weight z score was 0.18 (95% confidence interval [CI]: -0.35, -0.01) lower with each 10 ug/m3 increases of ozone exposure during 2 months before conception, and 0.12 (95% CI: -0.23, -0.01) lower with exposures during the 5th month of pregnancy. No statistically significant association was observed during other months in the preconception and gestation periods.Conclusions: High levels of ambient ozone exposures during two months before conception and around 5th months of gestation may be associated with lower birth weight.

Associations of sperm telomere length with semen parameters, clinical outcomes and lifestyle factors in human normozoospermic samples.

Many studies have demonstrated that lifestyle factors can affect sperm quality and fertility. Sperm telomere length (STL) has been reported as potential biomarker or sperm quality. However, no studies have investigated how lifestyle factors can affect STL and associated clinical outcomes. The purpose of this manuscript is to investigate any association between STL with lifestyle factors, semen parameters and clinical outcomes. Sperm telomere length was measured using real-time PCR in normozoospermic male partners (n=66) of couples undergoing ART treatment. Each participant also completed a detailed questionnaire about general lifestyle. Linear regression univariate analysis and ANCOVA were performed to respectively determine correlations between STL and study parameters or identify statistically significant differences in STL while controlling for age, BMI and other factors. Using a linear regression model, STL is positively correlated with in vitro fertilization success (n=65, r = 0.37, P = .004) but not with embryo cleavage rates and post-implantation clinical outcomes including gestational age-adjusted birth weight. No associations were observed between STL and sperm count, concentration or progressive motility. We further found that STL did not associate age, BMI, health or lifestyle factors. In somatic cells, the rate of telomere shortening is influenced by a number of lifestyle factors such as smoking, diet and occupation. However, little is known about how lifestyle factors affect STL and subsequently reproductive outcome. Out data suggest that STL might have an important role mechanistically for fertilization rate regardless of sperm parameters and lifestyle factors. The results of this study demonstrate that STL is associated with in vitro fertilization rates, but not with semen parameters nor lifestyle factors. Further investigations are warranted to identify the potential variation of STL overtime to clarify its significance as a potential biomarker in ART.

151. Aldosterone as independent predictor of placental and birth weights: Odense Child Cohort study

Introduction Aldosterone is involved in plasma volume expansion and its levels, along with the levels of other members of the renin-angiotensin-aldosterone system (RAAS), are increased in healthy pregnancy. Aldosterone appears to contribute to an optimal fetal development by enhancing placental growth factor (PlGF) expression and trophoblast cell proliferation. In contrast to normal pregnancy, aldosterone is suppressed in preeclampsia. Hypothesis Aldosterone independently contributes to placental and fetal growth. Methods The project is based on data from the Odense Child Cohort, a prospective population-based study from the Municipality of Odense, Denmark, currently with 2500 active families. The participants were recruited between 2010 and 2012. To analyze plasma aldosterone levels and urinary aldosterone excretion (UAldoV), we used a subsample of 637 urine samples (24-h collections) from gestational week 28. Plasma aldosterone and UAldoV were determined by a commercially available ELISA. Predictive values of aldosterone were assessed by multiple regression analysis. Primary outcomes were placental weight (PW) and gestational age-adjusted birth weight Z-score (BW sds). Results UAldoV, but not plasma aldosterone concentration, independently contributed to PW and BW sds (adjusted β coefficients ± SEM: 3.21 ± 1.51, p Discussion At 28 weeks of gestation, 24-h urinary aldosterone excretion was an independent predictor of placental and birth weights. In perspective, aldosterone could be a candidate biomarker for future screening and monitoring programs of high-risk pregnancies. Our findings support the physiological role for aldosterone and likely NaCl conservation for normal pregnancy. Mineralocorticoid supplementation could be considered for pregnancies with high risk for IUGR in order to achieve elevated levels of mineralocorticoids and thus benefit placental and fetal development.

The effect of portable HEPA filter air cleaner use during pregnancy on fetal growth: The UGAAR randomized controlled trial

BackgroundFine particulate matter (PM2.5) exposure may impair fetal growth. Aims/objectivesOur aim was to assess the effect of portable high efficiency particulate air (HEPA) filter air cleaner use during pregnancy on fetal growth. MethodsThe Ulaanbaatar Gestation and Air Pollution Research (UGAAR) study is a single-blind randomized controlled trial conducted in Ulaanbaatar, Mongolia. Non-smoking pregnant women recruited at ≤18 weeks gestation were randomized to an intervention (1–2 air cleaners in homes from early pregnancy until childbirth) or control (no air cleaners) group. Participants were not blinded to their intervention status. Demographic, health, and birth outcome data were obtained via questionnaires and clinic records. We used unadjusted linear and logistic regression and time-to-event analysis to evaluate the intervention. Our primary outcome was birth weight. Secondary outcomes were gestational age-adjusted birth weight, birth length, head circumference, gestational age at birth, and small for gestational age. The study is registered at ClinicalTrials.gov (NCT01741051). ResultsWe recruited 540 participants (272 control and 268 intervention) from January 9, 2014 to May 1, 2015. There were 465 live births and 28 losses to follow up. We previously reported a 29% (95% CI: 21, 37%) reduction in indoor PM2.5 concentrations with portable HEPA filter air cleaner use. The median (25th, 75th percentile) birth weights for control and intervention participants were 3450 g (3150, 3800 g) and 3550 g (3200, 3800 g), respectively (p = 0.34). The intervention was not associated with birth weight (18 g; 95% CI: −84, 120 g), but in a pre-specified subgroup analysis of 429 term births the intervention was associated with an 85 g (95% CI: 3, 167 g) increase in mean birth weight. ConclusionsHEPA filter air cleaner use in a high pollution setting was associated with greater birth weight only among babies born at term.

Correlation of cord blood telomere length with birth weight

BackgroundIntrauterine growth restriction affects 3% of newborns; and the lightest 10% of whom are classified as small for gestational age (SGA). These low-birth weight newborns are at increased risk of neonatal morbidity such as hypoxia and hypoglycaemia. In later life, they are at higher risk of several age-related diseases such as cardiovascular and metabolic disorders and dementia. As having short telomeres is also associated with these diseases, we tested if these newborns might already start with shorter telomeres at birth.FindingsRelative telomere lengths were determined using quantitative real-time PCR in cord blood samples from 195 newborns of Chinese ancestry. Based on the telomere length normalised to a single copy gene and a reference DNA sample as internal control, we found statistically significant correlations between relative telomere length and both unadjusted and gestational age-adjusted birth weight, with the lighter newborns having shorter telomeres. The SGA birth weight group comprising the bottom 10% of the samples also had the shortest telomeres compared to the medium and heaviest birth weight groups.ConclusionsOur results indicate that there is reduction of cord blood telomere length for newborns with lower birth weight.

Relationship Between Birth Weight and the Double Product in Childhood, Adolescence, and Adulthood (from the Bogalusa Heart Study)

Low birth weight is associated with cardiovascular disease and its risk factors, including heart rate and blood pressure. Therefore, we examined the hypothesis that birth weight is related to blood pressure-heart rate product (double product, DP), an index of oxygen consumption and workload of the heart, at different ages. Heart rate at rest, blood pressure at rest, and birth weight data were available in 2,340 children (4 to 11 years), 1,621 adolescents (12 to 19 years), and 2,315 adults (20 to 52 years) from the Bogalusa Heart Study (total n = 6,276). After adjustment for age, sex, race, and body mass index, gestational age-adjusted birth weight was inversely associated with DP, with per 100-g decrease in birth weight associated with an increase of 12.8, 22.9, and 23.2 beats/min × mmHg in DP in children (p = 0.016), adolescents (p = 0.0007), and adults (p = 0.0006), respectively. An amplifying trend of the association with age was observed in the total sample (p = 0.002). In conclusion, birth weight is associated with increased DP beginning in childhood, which may partly mediate the association between low birth weight and increased cardiovascular risk later in life.

Timing of Excessive Weight Gain During Pregnancy Modulates Newborn Anthropometry.

Excessive gestational weight gain (GWG) is associated with increased birth weight and neonatal adiposity. However, timing of excessive GWG may have a differential impact on birth outcomes. The objective of this study was to compare the effect of early and mid/late excessive GWG on newborn anthropometry in the context of the Canadian clinical recommendations that are specific for first trimester and for second/third trimesters based on maternal pre-pregnancy BMI. We included 607 glucose-tolerant women in our main analyses, after excluding women who had less than the recommended total GWG. Maternal body weight was measured in early pregnancy, mid-pregnancy, and late pregnancy. Maternal and fetal clinical outcomes were collected, including newborn anthropometry. Women were divided into four groups according to the Canadian guidelines for GWG in the first and in the second/third trimesters: (1) "overall non-excessive" (reference group); (2) "early excessive GWG"; (3) "mid/late excessive GWG"; and (4) "overall excessive GWG." Differences in newborn anthropometry were tested across GWG categories. Women had a mean (±SD) pre-pregnancy BMI of 24.7 ±5.2kg/m(2) and total GWG of 15.3 ± 4.4 kg. Women with mid/late excessive GWG gave birth to heavier babies (gestational age-adjusted birth weight z-score 0.33 ± 0.91) compared with women in the reference group (0.00 ± 0.77, P= 0.007), whereas women with early excessive GWG gave birth to babies of similar weight (gestational age-adjusted z-score 0.01 ± 0.86) to the reference group (0.00 ± 0.77, P= 0.84). When we stratified our analyses and investigated women who gained within the recommendations for total GWG, mid/late excessive GWG specifically was associated with greater newborn size, similar to our main analyses. Excessive GWG in mid/late pregnancy in women who did not gain weight excessively in early pregnancy is associated with increased birth size, even in those who gained within the Canadian recommendations for total GWG.

Racial differences in IGF1 methylation and birth weight

BackgroundThe birth weight of Black neonates in the United States is consistently smaller than that of their White counterparts. Epigenetic differences between the races may be involved in such disparities. The goal of these analyses was to model the role of IGF1 methylation in mediating the association between race and birth weight. Data was collected on a cohort of 87 live born infants. IGF1 methylation was measured in DNA isolated from the mononuclear fraction of umbilical cord blood collected after delivery. Quantitative, loci-specific methylation was assessed using the Infinium HumanMethylation27 BeadArray (Illumina Inc., San Diego, CA). Locus specific methylation of the IGF1 CpG site was validated on a subset of the original sample (N = 61) using pyrosequencing. Multiple linear regression was used to examine relationships between IGF1 methylation, race, and birth weight. A formal mediation analysis was then used to estimate the relationship of IGF1 methylation to race and birth weight.ResultsBlack race was associated with a 7.45% decrease in gestational age-adjusted birth weight (aBW) (P = 0.04) and Black infants had significantly higher IGF1 methylation than non-Black infants (P < 0.05). A one standard deviation increase in IGF1 methylation was associated with a 3.32% decrease in aBW (P = 0.02). Including IGF1 methylation as a covariate, the effect of Black race on aBW was attenuated. A formal mediation analysis showed that the controlled direct effect of Black race on aBW was −6.26% (95% CI = −14.15, 1.06); the total effect of Black race on IGF1 methylation was −8.12% (95% CI = −16.08, −0.55); and the natural indirect effect of Black race on aBW through IGF1 methylation was −1.86% (95% CI = −5.22, 0.18)ConclusionThe results of the mediation analysis along with the multivariable regression analyses suggest that IGF1 methylation may partially mediate the relationship between Black race and aBW. Such epigenetic differences may be involved in racial disparities observed in perinatal outcomes.

The association between maternal blood pressures and offspring size at birth in Southeast Asian women.

BackgroundMaternal blood pressures in pregnancy is an important determinant of offspring size at birth. However, the relationship between maternal blood pressures and offspring’s size at birth is not consistent and may vary between ethnic groups. We examined the relationship between maternal peripheral and central blood pressures and offspring size at birth in an Asian multi-ethnic cohort, and effect modifications by maternal ethnicity and obesity.MethodsWe used data from 713 participants in the Growing Up in Singapore Towards Healthy Outcomes study consisting of pregnant Chinese, Malay and Indian women recruited from two tertiary hospitals between 2009 to 2010. Peripheral systolic and diastolic blood pressures (SBP and DBP), and central SBP and pulse pressure (PP) were measured around 27 weeks of gestation. Biometric parameters at birth were collected from medical records.ResultsAfter adjusting for maternal and fetal covariates, each 1-SD increase (10.0 mmHg) in central SBP was inversely associated with birth weight (−40.52 g; 95% confidence interval (CI) -70.66 to −10.37), birth length (−0.19 cm; −0.36 to −0.03), head circumference (−0.12 cm; −0.23 to −0.02) and placental weight (−11.16 g; −20.85 to −1.47). A one-SD (11.1 mmHg) increase in peripheral SBP was also associated with lower birth weight (−35.56 g; −66.57 to −4.54). The inverse relations between other blood pressure measures and offspring size at birth were observed but not statistically significant. Higher peripheral SBP and DBP and central SBP were associated with increased odds of low birth weight (defined as weight <2500 g) and small for gestational age (defined as <10th percentile for gestational age adjusted birth weight). Maternal adiposity modified these associations, with stronger inverse associations in normal weight women. No significant interactions were found with ethnicity.ConclusionsHigher second-trimester peripheral and central systolic pressures were associated with smaller offspring size at birth, particularly in normal weight women. Findings from this study reinforces the clinical relevance of antenatal blood pressure monitoring.Electronic supplementary materialThe online version of this article (doi:10.1186/s12884-014-0403-1) contains supplementary material, which is available to authorized users.

Fetal and infant growth patterns and kidney function at school age.

Low birth weight is associated with ESRD. To identify specific growth patterns in early life that may be related to kidney function in later life, we examined the associations of longitudinally measured fetal and infant growth with kidney function in school-aged children. This study was embedded in a population-based prospective cohort study among 6482 children followed from fetal life onward. Fetal and childhood growth was measured during second and third trimesters of pregnancy, at birth, and at 6, 12, 24, 36, and 48 months postnatally. At the age of 6 years, we measured kidney volume by ultrasound. GFR was estimated using blood creatinine levels. Higher gestational age-adjusted birth weight was associated with higher combined kidney volume and higher eGFR (per 1 SD score increase in birth weight; 1.27 cm(3) [95% confidence interval, 0.61 to 1.93] and 0.78 ml/min per 1.73 m2 [95% CI, 0.16 to 1.39], respectively). Fetal weight, birth weight, and weight at 6 months were positively associated with childhood kidney volume, whereas higher second trimester fetal weight was positively associated with higher GFR (all P values<0.05). Fetal and childhood lengths were not consistently associated with kidney function. In this cohort, lower fetal and early infant weight growth is associated with smaller kidney volume in childhood, whereas only lower fetal weight growth is associated with lower kidney function in childhood, independent of childhood growth. Whether these associations lead to an increased risk of kidney disease needs to be studied further.

Lifetime racism and blood pressure changes during pregnancy: Implications for fetal growth.

Research suggests that exposure to racism partially explains why African American women are 2 to 3 times more likely to deliver low birth weight and preterm infants. However, the physiological pathways by which racism exerts these effects are unclear. This study examined how lifetime exposure to racism, in combination with maternal blood pressure changes during pregnancy, was associated with fetal growth. African American pregnant women (n = 39) reported exposure to childhood and adulthood racism in several life domains (e.g., at school, at work), which were experienced directly or indirectly, meaning vicariously experienced when someone close to them was treated unfairly. A research nurse measured maternal blood pressure at 18 to 20 and 30 to 32 weeks gestation. Standardized questionnaires and trained interviewers assessed maternal demographics. Neonatal length of gestation and birth weight data were collected from medical charts. Childhood racism interacted with diastolic blood pressure to predict birth weight. Specifically, women with two or more domains of indirect exposure to racism in childhood and increases in diastolic blood pressure between 18 and 32 weeks had lower gestational age adjusted birth weight than the other women. A similar pattern was found for direct exposure to racism in childhood. Increases in diastolic blood pressure between the second and third trimesters predicted lower birth weight, but only when racism exposure in childhood (direct or indirect) was relatively high. Understanding pregnant African American women's lifetime direct and indirect experiences with racism in combination with prenatal blood pressure may improve identification of highest risk subgroups within this population.