Lifestyle changes during pregnancy may improve outcomes for obese women and their babies

LONDON, ON – It has been shown that women who are obese are at higher risk for adverse pregnancy outcomes. Not only do one third of obese pregnant women develop gestational diabetes, they are also more likely to deliver babies with neonatal adiposity – a term to describe an increased amount of fat. These babies are more likely to be obese in childhood which increases their risk of developing type 2 diabetes. 

In a new analysis from a multi-centre randomized clinical trial, researchers found that counselling obese expectant mothers on both healthy eating and physical activity during pregnancy reduced the risk of neonatal adiposity. In particular, less time spent sitting was associated with improved outcomes. This is the first study to show that a lifestyle change during a mother’s pregnancy can influence the amount of fat present in a baby at birth. 

The DALI Lifestyle Study included expectant mothers classified as obese from nine European countries and a total of 334 babies. The expectant mothers were randomized to receive lifestyle counselling on physical activity, healthy eating or a combination of the two during pregnancy, and were compared to a control group of women who received no counselling. 

The study found that mothers who receive combined counselling on healthy eating and physical activity gain less weight during pregnancy, increase their physical activity, improve their eating habits and reduce their time spent sitting. But, most importantly, their babies have less fat at birth when compared to babies from women who did not receive lifestyle advice.

Since weight alone is not an accurate marker, the amount of fat for each baby was determined through a number of measures including skinfold thickness and estimated fat percentage. 

“We wanted to take a closer look at what specific lifestyle change was related to this reduction in fat. Through further analysis, we found that it was the amount of time spent simply sitting,” says Dr. David Hill, Lawson Scientist and collaborator on this study. “As part of recommendations on healthy eating and physical activity, pregnant women who are obese should be counselled on ways to reduce the time they spend sitting.” 

Less time spent sitting was also associated with reduced levels of leptin, a hormone produced by fat tissue and the placenta. When levels become too high during pregnancy, this hormone can inhibit insulin production and increase the risk of gestational diabetes. Reducing levels of this hormone during pregnancy may help lower risk of gestational diabetes and prevent transfer of excess nutrients to the fetus, which is then stored as fat. 

“Treating pregnant women with medication to control gestational diabetes risks unwanted effects on the fetus,” explains Dr. Hill, also a Professor at the Schulich School of Medicine & Dentistry, Western University. “Identifying effective lifestyle modifications would be the safest, most affordable method of preventing short-term and long-term disease for both the mother and baby.” 

Dr. Hill’s research focuses on understanding gestational diabetes. His team is testing novel drug interventions with the potential to prevent the disease. This includes exploring new molecules identified through the DALI study.

The study, “A reduction in sedentary behaviour in obese women during pregnancy reduces neonatal adiposity: The DALI randomized controlled trial,” is published in Diabetologia. Lawson researchers designed the research database used for the DALI study, and archived and supervised use of the research data. 

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