Researchers have found that women who engage in moderate physical activity during pregnancy are less likely to have gestational diabetes, and the exercise also helps to reduce maternal weight gain.
"Exercise is not something to be feared during pregnancy - the moderate levels of exercise used in these studies had significantly positive effects on health and were found to be safe for both mother and baby," said lead author of the study Gema Sanabria-Martinez from Virgen de la Luz Hospital in Spain.
Gestational diabetes is one of the most frequent complications of pregnancy. It is associated with an increased risk of serious disorders such as hypertension, preterm birth, and with induced or caesarean birth.
It can have long term effects on the mother including long term impaired glucose tolerance and Type-2 diabetes.
The children of mothers with gestational diabetes are more likely to become overweight or obese and have a higher risk of developing diabetes themselves.
Gaining more weight than is recommended during pregnancy carries similar risks, and these women are also less likely to lose the excess weight after the baby is born.
In this study, analysis of 13 trials, involving more than 2,800 women, found that exercise reduced the risk of gestational diabetes by more than 30 percent - for women who exercised throughout pregnancy this was even greater (36 percent).
This effect was strongest for women who combined toning, strength, flexibility and aerobic exercise.
Exercise was also helpful in reducing excessive weight gain -- those who exercised were on average a kilogram lighter.
This held true for the weight gain even if the exercise programme was started in the second trimester of pregnancy.
The study was published in BJOG: An International Journal of Obstetrics and Gynaecology.