Antibiotics in Pregnancy Increase Child Obesity Risk

Children exposed to antibiotics during the second or third trimester of pregnancy have an 84% higher risk of being obese at age 7 compared with children who were not exposed to the drugs in utero, according to new research published in the Journal of Obesity.

The study also found a 46% higher risk of childhood obesity in babies delivered by Caesarean section, regardless of elective or non-elective procedures.

According to the study authors, both findings may relate to microbial exposure during pregnancy and birth, given that disturbances in the transmission of bacteria from mother to the child are thought to place offspring at risk for various health conditions, including obesity. Either situation is believed to disrupt the normal transmission of bacteria from mother to child, as well as disturb the child’s bacterial balance.

The study included healthy, non-smoking pregnant women who were recruited from prenatal clinics at 2 New York hospitals. The 436 women and their offspring were then followed for 7 years. Antibiotic use during the second or third trimester occurred in 16% of participants.

“Our findings on prenatal antibiotics and risk for offspring obesity are novel, and thus warrant replication in other prospective cohort studies,” said Noel Muller, PhD, postdoctoral researcher fellow at Columbia University’s Mailman School of Public Health, in a press release. “If these findings hold up, they suggest new mechanisms through which childhood growth trajectories are influenced at the earliest stages of development. Our findings should not discourage antibiotic use when they are medically needed, but it is important to recognize that antibiotics are currently overprescribed.”