Dataset Information

Maternal prepregnancy BMI and size at birth: race/ethnicity-stratified, within-family associations in over 500,000 siblings.

ABSTRACT:

Purpose

To estimate racial/ethnic-stratified effects of maternal prepregnancy BMI on size for gestational age at birth, by comparing siblings within families.

Methods

This study examined linked vital statistics and patient discharge data from 580,960 infants born to 278,770 women in the State of California (2007-2012). To control for family-level confounding, we used fixed effects multinomial regression, modeling size for gestational age (small [SGA], appropriate, large [LGA]) as a function of maternal BMI (underweight, normal weight, overweight, obesity class I, II, III) and time-varying covariates. We conducted overall and race/ethnicity-stratified (non-Hispanic white, black, Asian; Hispanic) analyses. For comparison, we fit analogous random effects models, which do not control for family-level confounding.

Results

In fixed effects models, maternal BMI was most strongly associated with LGA in non-Hispanic white women, reaching 6.7 times greater for class III obesity (OR [95% CI]: 6.7 [5.1, 8.7]); and weakest in black women (OR [95% CI]: 3.0 [1.5, 5.7]). Associations with SGA were similar across race/ethnicity. Compared with random effects estimates, fixed effects were most attenuated for LGA associations among racial/ethnic minority women.

Conclusions

Maternal prepregnancy BMI was differentially associated with size for gestational age across racial/ethnic groups, with the strongest family-level confounding in racial/ethnic minority women.

SUBMITTER: Boone-Heinonen J

PROVIDER: S-EPMC7315911 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundParental body mass index (BMI) is associated with pregnancy outcomes. But the effect of parental prepregnancy BMI on offspring conceived via in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), especially the birth defect, remains to be determined. This study aimed to investigate the associations of parental prepregnancy BMI with neonatal outcomes and birth defect in fresh embryo transfer cycles.MethodsWe conducted a retrospective cohort study including 5741 couples in their first fresh IVF/ICSI cycles admitted to Women's Hospital, School of Medicine, Zhejiang University from January 2013 to July 2016. The primary outcome was birth defects, which was classified according to the International Classification of Diseases, 10th Revision. Secondary outcomes included preterm delivery rate, infant gender, birth weight, small-for-gestational age (SGA) and large-for-gestational age (LGA). Multilevel regression analyses were used to assess the associations of parental prepregnancy BMI with neonatal outcomes and birth defect.ResultsIn singletons, couples with prepregnancy BMI ≥25 kg/m2 had higher odds of LGA than those with BMI < 25 kg/m2. The birth defect rate was significantly higher when paternal prepregnancy BMI ≥25 kg/m2 in IVF cycles (aOR 1.82, 95% CI 1.06-3.10) and maternal BMI ≥25 kg/m2 in ICSI cycles (aOR 4.89, 95% CI 1.45-16.53). For subcategories of birth defects, only the odds of congenital malformations of musculoskeletal system was significantly increased in IVF offspring with paternal BMI ≥25 kg/m2 (aOR 4.55, 95% CI 1.32-15.71). For twins, there was no significant difference among four groups, except for the lower birth weight of IVF female infants.ConclusionsParental prepregnancy BMI ≥25 kg/m2 is associated with higher incidence of LGA in IVF/ICSI singletons. Paternal prepregnancy BMI ≥25 kg/m2 was likely to have higher risk of birth defect in IVF offspring than those with BMI < 25 kg/m2, particularly in the musculoskeletal system. It is essential for overweight or obesity couples to lose weight before IVF/ICSI treatments.