The largest study of its type sought to pinpoint when the link between weight gain in pregnancy and childhood obesity occurs.
A mother’s early weight gain has the greatest effect on a baby’s size at birth and later on in childhood, according to a study of more than 16,000 mothers appearing today in the journal Obesity.
The first 24 weeks matter the most, regardless of how much a mother gains later in pregnancy, according to the findings. The study, which gathered data from 16,218 women in China throughout their pregnancies, found that infants born to women who gained more weight than recommended by Institute of Medicine guidelines before the 24th week were 2.5 times more likely to be born large.
Many studies have linked a mother’s obesity and weight gain during pregnancy with a child’s obesity, but no study of this size has tried to pinpoint when during pregnancy the problem occurs.
Researchers said it is critical to educate women planning to start families that the time to affect a child’s long-term health starts even before pregnancy begins. Healthy diets, exercise, and in some cases weight loss should be encouraged before a woman tries to become pregnant to give a baby the best chance at good health and lower cardiovascular risk.
“Obstetrician gynecologists need to begin to educate patients who are pregnant or planning to become pregnant on the implications of weight gain in pregnancy on infant outcomes and the development of childhood obesity,” Leanne M. Redman, PhD, FTOS, who led the study, said in a statement. Redman is association professor and director of the Reproductive Endocrinology and Women’s Health Lab at LSU Pennington Biomedical Research Center.
In an accompanying editorial, Cheryce L. Harrison, PhD, said the results “validate previous literature in smaller cohorts while notably advancing this field of research in one of the largest, most well-defined mother-infant cohorts.”
Obesity is the official journal of The Obesity Society, which announced the findings.
Broskey NT, Wang P, Li N, et al. Early pregnancy weight gain exerts the strongest effect on birth weight, posing a critical time to prevent childhood obesity. Obesity. 2017;25(9):1569-1576. DOI: 10.1002/oby.21878.