In a longitudinal birth cohort study, Noel T. Mueller, PhD, Columbia University, and researchers studied 436 mothers and their children from birth until aged 7 years (when body composition was measured), gathering data on antibiotic use from interviews. After controlling for gestational age, birth weight, breast-feeding, maternal body mass index and socioeconomic status, among other variables, they found that antibiotic use during the second and third trimesters was associated with an 84% increased risk for obesity in the child. Information on prenatal antibiotics and mode of delivery was collected at birth, along with other control factors.
“In our study, children born by C-section delivery or to mothers who used antibiotics in the second or third trimester of pregnancy had higher risk of obesity,” according to Mueller, postdoctoral fellow in nutrition and population health, department of epidemiology and Institute of Human Nutrition.
â“The findings . . . are consistent with other studies on this topic, suggesting that reducing the rates of C-section may help lower the rate of childhood obesity in the United States and abroad,” she said. “Our findings on prenatal antibiotics and childhood obesity are novel, and therefore need to be replicated before any conclusions are made about their implications for hospital decision makers.
“If these findings hold up, they suggest new mechanisms through which childhood growth trajectories are influenced at the earliest stages of development,” Mueller continued. “Our findings should not discourage antibiotic use when they are medically needed, but it is important to recognize that antibiotics are currently overprescribed.”
According to Mueller, the findings are consistent with a series of papers that looked at data on Cesarean section, “thus providâingâ new evidence in support of the hypothesis that Cesarean section independently contributes to the risk of childhood obesity,” she said.