Obese women can lose weight and it won't hurt the baby

Jun 8 2007

Most women who are obese can safely exercise and diet to lose weight during pregnancy, according to a small pilot study conducted by Saint Louis University researchers.

“Doctors hadn't encouraged pregnant women who were obese to limit their weight gain or have them lose weight because they were afraid it would hurt the baby,” says Raul Artal, M.D., principal investigator and chair of the department of obstetrics, gynecology and women's health at Saint Louis University.

“We found that obese women do not have to gain any weight, and, in fact, can lose weight and it won't hurt the baby. Pregnancy is an ideal time to start an exercise and fitness program, particularly for women who are obese.”

Dr. Artal is an internationally recognized expert who has conducted extensive research on exercise during pregnancy and is the lead author of the American College of Obstetricians and Gynecologists' current guidelines on exercise for pregnant women.

The new research flies in the face of the “eat for two” and “take it easy” advice that obstetricians gave to a past generation of moms-to-be.

“There are so many more obese women and men. We are witnessing an epidemic of overweight and obesity,” Dr. Artal says. “Pregnancy seems to be an ideal time for behavior modification.”

Pregnant women are more likely to regularly see a doctor and tend to be highly motivated to make lifestyle changes that protect the health of their babies, he added.

For this study, Dr. Artal and his colleagues examined two groups of pregnant women who were obese and had gestational diabetes, a condition common in about 7 percent of all pregnancies. Of the 96 women studied, 39 dieted and exercised to control their weight and 57 followed the diet routinely given to patients who have gestational diabetes.

Those who exercised were supervised riding a semi-recumbent stationary cycle or walking on a treadmill at least once a week. They also were encouraged to maintain an exercise routine the other six days of the week. Half of the women in the group that exercised said they worked out for at least 30 minutes a day, five times a week, which is the recommended exercise guideline for the non-pregnant population.

Significantly more women who exercised and dieted either lost or maintained their weight than women in the group that followed the standard diabetic diet, the study found.

Findings suggest the babies born to women who lost or maintained their weight were more likely to be of normal size. Infants born to women who gained weight were more likely to be bigger – 8 pounds, 8 ounces and heavier.

More women who gained weight during pregnancy delivered their babies by Caesarian section than those who lost or kept their weight constant.

Limiting weight gain of obese women during pregnancy could have future health benefits for the moms, Dr. Artal says. They will retain less weight from the pregnancy, which decreases the incidence of type 2 diabetes and other obesity-related health problems.

Dr. Artal stressed that doctors and other health care providers need to do more in educating women, particularly those who are overweight or obese, about the importance of eating healthy and limiting the amount of weight they gain during pregnancy, and added a larger study is needed.

The research appears in the June issue of Applied Physiology, Nutrition, and Metabolism , which is published by Canada's National Research Council.

Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first M.D. degree west of the Mississippi River. Saint Louis University School of Medicine is a pioneer in geriatric medicine, organ transplantation, chronic disease prevention, cardiovascular disease, neurosciences and vaccine research, among others. The School of Medicine trains physicians and biomedical scientists, conducts medical research, and provides health services on a local, national and international level.