A new study has found a link between antibiotic use for pregnant moms and obesity risks for their children.

For the study, researchers evaluated 436 mothers and their children from birth until age seven. Using interviews, they assessed each mother's antibiotic use while she was pregnant. After considering factors such as gestational age, birth weight, breast-feeding, maternal body mass index (BMI) and socioeconomic status, the team found that antibiotic use during the second and third trimesters was associated with an 84 percent increased risk for obesity in the child.

Previous studies have shown that when babies are given antibiotics early in life they have a greater risk for obesity later on. But this is the first time that researchers have looked at the link between maternal antibiotic use — specifically that in the second or third trimester of pregnancy — and the risk for obesity in her children.

The study, published in the International Journal of Obesity, was conducted by a team of researchers at Columbia University. Researchers also found that children of women who gave birth via cesarean section — whether or not it was elective — were 46 percent more likely to be obese than children born via vaginal delivery.
The study did not look at what types of antibiotics the mothers were using, nor did it factor in what type of infections the antibiotics were treating — two components that could be a more critical factor than the use of antibiotics alone. 
Researchers are just beginning to understand the role played by bacteria that normally inhabit the digestive tract and their importance in maintaining our overall health.
Prenatal antibiotics linked to childhood obesity
Children exposed in second or third trimester could have serious weight gain later in life.