First clinical trial to test a weight maintenance program for obese pregnant women

More than half of women in the United States are overweight or obese when they become pregnant, and most go on to gain more than the recommended amount during pregnancy. The excess weight can lead to a myriad of complications, including preeclampsia, diabetes, bigger babies, C-sections, birth injuries, and weight retention after pregnancy.

In order to reduce these complications, Kaiser Permanente is launching the first clinical trial to help obese women control their weight during pregnancy. The "Healthy Moms" study, funded by a $2.2 million grant from the National Institute of Child Health and Human Development, will begin recruiting this month.

"The goal of the study is to keep obese pregnant women from gaining weight. We believe they can safely maintain their pre-pregnancy weight and deliver healthier babies," says Kim Vesco, MD, MPH, a practicing OB/GYN and researcher at the Kaiser Permanente Center for Health Research who will direct the study.

This is the first study to test a weight maintenance program for obese pregnant women, and the first to use weekly support groups as part of the intervention. A small study in Denmark did limit excess weight gain in obese pregnant women, but they still gained an average of 14.5 pounds. Two other larger studies failed to prevent excessive weight gain in obese and overweight pregnant women.

"It may seem counterintuitive to suggest that women control their weight during pregnancy, but these women are already carrying between 50 and 100 extra pounds--and for them any more weight gain could be very dangerous," said Vic Stevens, PhD, principal investigator who has studied weight loss and weight maintenance for more than 30 years.

The Institute of Medicine recently set an upper limit on the amount of weight obese women should gain during pregnancy. The old guideline, set in 1990, suggested at least 15 pounds; the new guideline, set in May 2009, recommends 11-20 pounds.

"The IOM guideline for weight gain in obese pregnant women hasn't been evaluated in a randomized controlled trial, and our study is challenging the guideline," said Vesco. "We know that excessive weight gain leads to more complications, and we are hoping to show that obese women who maintain their weight will actually have better outcomes."

The "Healthy Moms" trial will enroll 180 obese pregnant women from Washington and Oregon who are members of the Kaiser Permanente health plan: half will receive one-time dietary and exercise advice; the other half will attend two individual counseling sessions and then weekly group counseling for the remainder of their pregnancy. Women who attend the sessions will be weighed and encouraged to keep and turn in daily food and exercise diaries. Professional weight counselors will facilitate the groups and help motivate the women with behavior change techniques.

The study will follow women throughout their pregnancies to find out how much weight they gain, how large their babies are, and how much weight they retain one year after they give birth. It will also look at birthing complications, the baby's growth and feeding practices, and whether the mother continues with dietary changes after the baby is born. The study will recruit women for 18 months, and preliminary results are expected in three years.

Tips for Controlling Excess Weight Gain During Pregnancy

• Every day, eat 8-12 fruit and vegetable servings, 3 servings of low-fat dairy, 5-9 ounces of protein-rich foods, 6-10 servings of whole grains, and 3-7 teaspoons of healthy fat (e.g., olive or canola oil, nuts).
• Eat regular meals and small healthy snacks between meals.
• Reduce fat to less than 30 percent of calories.
• Reduce consumption of sweets and sweetened drinks.
• Keep a food diary to check for nutritional adequacy and portion management.
• Eat only 100-300 extra calories per day beyond what your calorie needs were before you became pregnant.
• Exercise 30 minutes on most days. If you aren't exercising, talk to your provider about how to start an exercise program.