Most women are healthy enough during pregnancy to start a light exercise program or maintain an exercise program they followed before becoming pregnant, but researchers note that exercise is not enough to control excessive weight gain during pregnancy. Gaining excessive amounts of weight while pregnant can have detrimental effects on the pregnancy and fetus. Fetal side effects of excessive weight gain during pregnancy can last into adulthood.

The study completed by Brazilian researchers and published in BJOG recruited 82 women between 14 and 24 weeks gestation. All participants measured at BMI of at least 26. BMI can be used to gauge weight. A normal weight BMI ranges from 18 to 25, so women in the study fell into the overweight or obese range.

The participant group was broken into two sub-groups. One group was educated on the importance of an exercise program during pregnancy, healthy nutrition and the effect of weight gain on fetal health. The remaining women were the control. They followed a typical prenatal care plan with no additional education.

At the end of all pregnancies, researchers found no statistical differences between the study and control groups. Women gained the same amount of weight. Fetal health was nearly identical and gestational diabetes was similar in both groups. Obese women gained about 23 pounds in the study group and 24 pounds in the control group. There was a slight difference in the overweight population, however. Overweight women in the study group gained about 22 pounds. The control group of overweight women gained about 36 pounds.

Researchers note that the participant pool used in this study was extremely small, but the outcome was clear. Overweight and obese women gained about the same amount of weight in both groups, whether or not exercise was added to their daily routine. Moreover, gestational diabetes appeared at the same rate between the two groups. Exercise is clearly not enough to stop weight gain or affect gestational diabetes.

Source: SL Nascimento, FG Surita, MA Parpinelli, S Siani, JL Pinto e Silva. BJOG. November 2011.