Excessive Pregancy Weight Gain Predicts Larger-Than-Average Birth Weight

Canadian researchers have found that overweight or obese women are more likely to give birth to above-average weight babies. The findings, published in the Journal of Maternal Fetal and Neonatal Medicine, are based on data from more than 4,000 pregnancies and births between 2002 and 2009. The data suggests that excessive gestational weight gain significantly increased the chances that mom would give birth to a baby whose weight was above the 90th percentile. They also found that excessive pregnancy weight gain was as “problematic” as pre-pregnancy weight/obesity.

“Obesity can become part of an inter-generational cycle,” said Dr. Kristi Adamo, co-author of the report, “Birth weight averages can be an indicator of the weight a child will carry through preschool and even into adulthood. It’s critical for a mother to understand that her healthy eating and lifestyle decisions during pregnancy will impact much more than a nine-month gestation period.”

Dr. Denis Prud’homme, co-author of this report and dean of the Faculty of Health Sciences writes, “Unfortunately, delivering a large baby increases the risk for many delivery-related complications in both mom and baby. But the takeaway here is that GWG is a modifiable risk factor that can and must be addressed during prenatal visits for all women.”

“It doesn’t matter if you’re categorized as normal weight, overweight or obese during pre-pregnancy — exceeding the 2009 Institute of Medicine GWG targets seems to have a growth promoting effect on the fetus,” explained co-author Zach Ferraro, a PhD student at the University of Ottawa.


Here are the The 2009 Institute of Medicine GWG targets for pregnancy weight gain, based on a woman’s BMI before becoming pregnant:

  • Underweight: Gain 28-40 pounds
  • Normal weight: Gain 25-35 pounds
  • Overweight: Gain 15-25 pounds
  • Obese: Gain 11-20 pounds

These are the guidelines for weight gain during pregnancy with twins, based on the mother’s pre-pregnancy BMI:

  • Normal weight: Gain 37-54 pounds
  • Overweight: Gain 31-50 pounds
  • Obese: Gain 25-42 pounds
  • Underweight: No weight gain guidelines are available because of insufficient data.

There’s been a LOT of news lately about how weight gain can impact birth and the baby’s weight and health (at birth and later in life), including one study showing that too little weight gain in pregnancy can lead to obesity in children. Staying within a healthy range seems to be the message. I must say, however, that I’ve known a lot of very healthy women who’ve gained 50 pounds, easily, and then given birth to healthy babies who start out and remain within the range of normal weight. I also come from a family of very tall Australian people- we have Scottish heads (apparently the biggest!) and we have babies over the 90th percentile, no worries. As always, these kinds of numbers have to interpreted along with other variables.



Photo: Snoozeboy/Flickr

Article Posted 4 years Ago
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