Obese women can safely gain no weight during pregnancy -- or even lose a few pounds --without harming their babies, says a study in Obstetrics & Gynecology.
Health Canada has long recommended that women who have a body mass index (BMI) or more than 27 should aim to gain 15 to 25 (7 to 11.5 kgs) during their pregnancy.
But the study found that women who ignore that advice and put on less than 15 pounds enjoyed better pregnancies, including:
- a lower tendency to develop preeclampsia (pregnancy-related high blood pressure)
- a lower tendency to deliver by caesarean section
- a greater chance of having a normal-weight baby
"Not only were there no deleterious effects, but there are benefits,'' said study author Dr. Raul Artal of Saint Louis University School of Medicine.
By analyzing the results of their study, the researchers were able to come up with optimal ranges of weight gain:
- for a BMI of 30-34.9, the best outcomes came with a weight gain of 10 to 25 pounds
- for a BMI of 35-39.9, gaining less than nine pounds was best
- for those with a BMI over 40, losing up to nine pounds was best.
The findings fuel growing concern that current weight-gain guidelines for pregnant women are outdated and don't take into account the nation's obesity epidemic.
Health Canada has long recommended that women who have a body mass index (BMI) or more than 27 should aim to gain 15 to 25 pounds (7 to 11.5 kgs) during their pregnancy. Women of normal weights are advised to gain 25 to 35 lbs. (11.5 to 16 kg)
In an accompanying editorial, Dr. Patrick Catalano of Case Western Reserve University, notes that the current guidelines were written when the concern was low birth weights.
That worry has now, of course, shifted to rising obesity. Obesity appears to increase a woman's risk of miscarriage and other serious complications, such as gestational diabetes.
Health Canada's current guidelines are based on advice issued by the Institute of Medicine, a private organization that advises both U.S. and Canadian federal governments. In the coming weeks, the IOM is expected to begin to gather evidence to decide whether its guidelines should be changed.
