Study: Lifestyle More Likely to Affect Child’s Weight Than Mom’s BMI

Experts have long said that maternal body mass index (BMI) affects the child’s birth weight. While this is true, a new study is finding that maternal BMI may not be a strong predictor of childhood obesity later on in life.

The study was published February 1 in BMC Medicine by researchers from University of Bristol and Imperial College London. They looked at data from two studies based in the U.K.: The Children of the 90s study based at the University of Bristol and the Born in Bradford study based in Bradford Teaching Hospitals NHS Foundation Trust.

The researchers analyzed birth weights, as well as BMI when the kids were 1, 4, 10 and 15 years old. They found that, while there is a moderate causal effect between maternal BMI and a child’s birth weight, this correlation between the two became weaker as the child aged. Researchers believe maternal BMI is not likely to be a strong predictor of childhood obesity and that it is instead more likely determined by environmental and lifestyle factors.

“We found that if women are heavier at the start of pregnancy this isn’t a strong cause of their children being heavier as teenagers,” Tom Bond, MD, lead author of the study and senior research associate at the University of Bristol, said in a press release. “Supporting women and men at all ages to keep a healthy weight will be needed to prevent obesity. It isn’t enough to just focus on women entering pregnancy.”

He also added, however, that keeping up a healthy weight during pregnancy wherever possible does have health benefits for both mom and baby, so healthcare professionals should still support women in maintaining a healthy pregnancy weight.

“It will be important to broaden this work to investigate other characteristics of mothers and fathers during pregnancy and a child’s early life that might affect children’s weight,” Bond continued.

To learn more about the study and its findings, visit Bristol.ac.uk.