Intrapartum Antibiotic Exposure and Body Mass Index in Children

Abstract

Background: Intrapartum antibiotic prophylaxis (IAP) reduces a newborn's risk of group B streptococcal infection (GBS) but may lead to an increased childhood body mass index (BMI).

Methods: This was a retrospective cohort study of infants (n = 223 431) born 2007-2015 in an integrated healthcare system. For vaginal delivery, we compared children exposed to GBS-IAP and to any other type or duration of intrapartum antibiotics to no antibiotic exposure. For cesarean delivery, we compared children exposed to GBS-IAP to those exposed to all other intrapartum antibiotics, including surgical prophylaxis. BMI over 5 years was compared using nonlinear multivariate models with B-spline functions, stratified by delivery mode and adjusted for demographics, maternal factors, breastfeeding, and childhood antibiotic exposure.

Results: In vaginal deliveries, GBS-IAP was associated with higher BMI from 0.5 to 5.0 years of age compared to no antibiotics (P < .0001 for all time points, ΔBMI at age 5 years 0.12 kg/m2, 95% confidence interval [CI]: .07-.16 kg/m2). Other antibiotics were associated with higher BMI from 0.3 to 5.0 years of age. In cesarean deliveries, GBS-IAP was associated with increased BMI from 0.7 years to 5.0 years of age (P < .05 for 0.7-0.8 years, P < .0001 for all other time points) compared to other antibiotics (ΔBMI at age 5 years 0.24 kg/m2, 95% CI: .14-.34 kg/m2). Breastfeeding did not modify these associations.

Conclusions: GBS-IAP was associated with a small but sustained increase in BMI starting at very early age. This association highlights the need to better understand the effects of perinatal antibiotic exposure on childhood health.

Keywords: body mass index; childhood obesity; delivery mode; intrapartum antibiotic prophylaxis.

Figure 1:

Adjusted body mass index (BMI), delta BMI, and their 95% CIs for children unexposed to intrapartum antibiotics (None), children exposed to intrapartum antibiotic prophylaxis as recommended for the prevention of perinatal group B streptococcal disease (GBS) and any other type or duration of intrapartum antibiotic administration (Other) stratified by delivery mode Covariate adjustments included demographics, maternal and birth-related factors included infant sex, gestational age at birth, birth weight, infant’s race/ethnicity (White, Black, Hispanic, Asian or Pacific Islander, other or unknown), year of birth, medical center of birth, maternal education, parity, maternal diabetes, maternal pre-pregnancy BMI, maternal gestational weight gain, maternal smoking during pregnancy, antepartum antibiotic exposure, neonatal antibiotic exposure, any breastfeeding, indirect antibiotic exposure during breastfeeding, and childhood antibiotic exposure.

Figure 2:

Comparison of adjusted excess BMI at 5 years of age associated with exposure to antibiotics during antepartum, intrapartum and postpartum periods *Δ BMI attributable to neonatal antibiotics is no longer significant when excluding children with low or high birth weight and/or complex care conditions (Vaginal delivery: −0.05 kg/m², 95% CI −0.11 kg/m² to 0.01 kg/m², P =0.090; Cesarean delivery: 0.02 kg/m², 95% CI −0.04 kg/m² to 0.09 kg/m², P =0.499; see eFigure 3). #Indirect antibiotic exposure through breastfeeding by a mother using antibiotics during the first 3 months after birth. The estimate for childhood exposure is per 14-day episode of antibiotic use. Covariates adjusted for included demographics, maternal and birth-related factors included infant sex, gestational age at birth, birth weight, infant’s race/ethnicity (White, Black, Hispanic, Asian or Pacific Islander, other or unknown), year of birth, medical center of birth, maternal education, parity, maternal diabetes, maternal pre-pregnancy BMI, maternal gestational weight gain, maternal smoking during pregnancy, antepartum antibiotic exposure, neonatal antibiotic exposure, any breastfeeding, indirect antibiotic exposure during breastfeeding, and childhood antibiotic exposure. The reference point reflects a population mean BMI at age 5 of 15.97 (SD 0.018) kg/m² for vaginally delivered children unexposed to intrapartum antibiotics (None) and 16.09 (SD 0.028) kg/m² for children delivered by Cesarean section and exposed to other intrapartum antibiotics (Other).