Antibiotics during pregnancy increases risk of obesity in childhood

19 November 2014

Taking antibiotics during pregnancy could increase the risk of a child becoming obese, a new study has found. 

The research, released by Columbia University's Mailman School of Public Health, found that pregnant women who took antibiotics in the second or third trimester of pregnancy had a higher risk of childhood obesity at age seven. 

Published online in the International Journal of Obesity, it also discovered that mothers who delivered their babies by a Caesarean section also had a higher risk of obesity for their children. 

The team used data from healthy, non-smoking, pregnant women who were part of the Northern Manhattan Mothers and Children Study from prenatal clinics at New York-Presbyterian Hospital and Harlem Hospital Center between 1998 and 2006. 

Some 727 mothers took part in the study and 436 were followed for seven years. Some 16 per cent of these mums had taken antibiotics in the second or trimester. It found that these children were at a 84 per cent higher risk of obesity, compared to children who were not exposed.

Although previous studies have indicated that antibiotics given to very young children could be linked to a greater chance of obesity, this is the first study to connect maternal use and being overweight.

Antibiotics target microbes in the mother, which could reach the child through the placenta, and researchers are starting to understand that disruption in the normal transmission of bacteria could have an impact on health.

The findings on prenatal antibiotics and risk for offspring obesity are new and therefore need further research, according to Dr Noel Mueller, postdoctoral research fellow at Columbia University's Mailman School of Public Health and Institute of Human Nutrition. 

"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," added Dr Mueller.

Independent of prenatal antibiotic usage, the study found that having a Caesarean section put the child at a 46 per cent higher risk of being obese in their early years. The researchers controlled for maternal age, ethnicity, birth weight, sex, breastfeeding in the first year, and gestational antibiotics or delivery mode.
"Our findings are consistent with a series of papers that looked at data on Caesarean section. While earlier studies suggested that childhood outcomes differ by whether the Caesarean section was elective or non-elective, we did not observe such evidence," said Dr Andrew Rundle, associate professor of Epidemiology at the Mailman School of Public Health. 

This means that the results provide new evidence to support the hypothesis that Caesarean sections independently contributes to the risk of childhood obesity, according to Dr Rundle. 

Similar to antibiotic use during pregnancy, Caesarean section birth is thought to reduce the normal transmission of bacteria from the mother to the child and to disturb the balance of bacteria in the child. 

Posted by Philip Briggs​


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