Putting on pounds while pregnant has stronger effect than pre-pregnancy weight on size of baby: study

TORONTO – A new Canadian study suggests that expectant mothers who exceed weight gain recommendations significantly increase the chance of giving birth to a larger baby.

Researchers from the Children’s Hospital of Eastern Ontario (CHEO) Research Institute, the University of Ottawa, and the Ottawa Hospital Research Institute studied over 4,000 mother and baby pairs in their report published in the Journal of Maternal Fetal and Neonatal Medicine Tuesday.

According to the CHEO Research Institute, one out of every two women of reproductive age (between 18-35 years) is overweight or obese. Overweight is defined as a body mass index (BMI) between 25 and 29.9, and obese is a BMI greater than 30. Calculate your BMI here.

The researchers found that independent of a woman’s BMI pre-pregnancy, excessive gestational weight gain increased the likelihood of giving birth to a large baby, putting both mom and baby at risk for health complications associated with C-sections, or metabolic problems later in life for the child.

While it may seem obvious that women who pack on more pounds during pregnancy will have larger babies, the key message is that gestational weight gain is a risk factor that can be changed to improve the health of the child, and the mother.

“Women of any BMI-normal weight or obese, have the control to gain within the recommendations, so they can work with their healthcare team to meet those recommendations,” study coauthor Zach Ferraro told Global News.

Ferraro is a PhD student in the human kinetics doctoral program at the University of Ottawa and part of the Healthy Active Living and Obesity (HALO) Research Group at the CHEO Research Institute.

Here are the latest gestational weight gain targets, courtesy of the Institute of Medicine:

Ferraro notes that many mothers-to-be are startled when told how little they need to add to their diet when pregnant, explaining that most women without complications don’t need to increase their caloric intake at all.

“They can maintain the growth and development with a two or three hundred calorie increase in the second and third trimester,” he says. “So that’s actually less than a Tim Hortons bagel.”

Tips that could help women from gaining too much weight during pregnancy include physical activity for 15 minutes three times per week and building up to 30 minutes four times per week. For people who are unaccustomed to activity, Ferraro recommends starting with the “five minute rule.”

“Try it for five minutes, because if you can get yourself up and moving, you generally start to feel better a little bit quicker, and you can carry that momentum forward,” he says.

Another tip is a healthful eating plan that’s high in fibre, full of green, leafy vegetables and avoiding foods rich in refined sugar and saturated fats.

For women who have a tendency to increase their caloric intake through sugar-sweetened beverages like pop or iced tea, make a healthy substitute with a squeeze of lemon or a lime in a glass of water. Ferraro says every little bit counts when it comes to healthy eating and exercise.

“We hope that they can maintain these behaviors in the postpartum, teach their children these behaviours, and then facilitate an intergenerational cycle of healthful behavior,” he says. “Try to think about what you put in, because you’re not eating like two, you’re eating for two.”

Ferraro notes that the study’s limitations include a primarily Caucasian participant sample, and not grouping women according to socio-economic status or education, which may have affected outcomes. Ferraro’s latest research focuses on the large scale intervention of strength and aerobic training with pregnant women as well as the underlying physiology involved in excessive weight gain and maternal obesity.