Regular exercise in pregnancy can protect against gestational diabetes in obese women

02 March 2017
Pregnant woman

A new study shows that regular exercise early in pregnancy reduces the frequency of gestational diabetes and pregnancy problems in overweight and obese women.

The study, published in the American Journal of Obstetrics and Gynaecology, involved a randomised controlled trial of 300 Chinese overweight or obese pregnant women.

Half the women were assigned to cycling three times a week for at least 30minutes, while the other half were in a control group continuing with normal activity.

The women began the trial before 12 weeks gestation and all had a BMI of greater than 24 to 28 (overweight) or greater than 28 (obese for the Chinese population).

Those in the exercise group had better outcomes than the control group, including:

  • Significantly lower rates of gestational diabetes mellitus (GDM): 22% developed the condition, compared with 40% in the control group
  • Lower gestational weight gain
  • Reduced insulin resistance levels
  • Fewer hypertensive disorders: 17% versus 19.3%
  • Lower rates of caesarean delivery: 29.5% versus 32.5%
  • Fewer pre-term births: 2.7% versus 4.4%
  • Fewer large-for-gestational-age babies: 14.3% versus 22.8%.

The authors say the fact the women began exercise early in pregnancy and that the programme was highly supervised may have played a key role in the effectiveness of the intervention.

“Our study clearly shows that exercise attenuates the increase in insulin resistance in the population of overweight and obese pregnant women at 25 weeks of gestation, possibly revealing the underlying mechanism by which exercise prevents GDM,” they say.

The authors say the study also identified that exercise was safe for pregnant women.  The moderate exercise did not cause any of the following:

  • The cervix to shorten
  • Increase the risk of miscarriage
  • Fetal loss
  • Pre-term birth
  • Reducing the mean gestational age at delivery.

“Considering the benefits and safety of exercise demonstrated in our study and other studies, increasing physical activity level of pregnant women is important.

“According to our study, regular moderate-intensity cycling at a frequency of no less than three sessions per week with each session lasting no less than 30 minutes begun in early pregnancy was safe and effective in preventing GDM in overweight and obese pregnant women.”

The authors advise that regular exercise should be recommended as an important part of antenatal care.

You can read the full study on the protective effects of exercise in pregnancy for obese and overweight women here.