Women who exercise during pregnancy are around a third less likely to develop gestational diabetes, and put on less weight - even if they normally do little or none, a study has found.
Gestational diabetes is a common pregnancy complication with up to 18 in every 100 women giving birth in England and Wales affected, although it is more prevalent in obese women.
It is associated with an increased risk of serious disorders such as pre-eclampsia, hypertension, pre-term birth, along with induced or Caesarean births and can also have long-term effects on the mother, including impaired glucose tolerance and type 2 diabetes.
The children of mothers with gestational diabetes are also more likely to become overweight or obese and have a higher risk of developing diabetes themselves.
The Spanish study looked at the results of enrolling healthy pregnant women who did little or no exercise into exercise programmes.
Analysis of 13 trials, involving more than 2,800 women, found that exercise reduced the risk of gestational diabetes by more than 30 per cent, while for women who exercised throughout pregnancy this was even greater at 36 per cent.
This effect was strongest for women who combined toning, strength, flexibility and aerobic exercise.
Exercise was also helpful in reducing excessive weight gain, with those who exercised a kilogram lighter on average.
This was also the case even if the exercise programme was started during the second trimester of pregnancy.
Lead author Gema Sanabria-Martinez, of Virgen de la Luz Hospital in Cuenca, said: “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.”
Mervi Jokinen, practice and standards professional adviser at the Royal College of Midwives, said: “It is important to keep physically active during pregnancy - moderate exercise will not harm the woman or her baby, recreational exercise such as swimming or brisk walking is known to be beneficial and this study appears to show a potential benefit of exercise in reducing the risk of gestational diabetes.
“The exercise pregnant women take should reflect their previous exercise regime. So for example it would not be appropriate for a woman who has done no exercise for many years to suddenly start running long distances in pregnancy. If women exercised regularly before pregnancy, they should be able to continue with no adverse effects.
“If women have not exercised routinely they should begin with no more than 15 minutes of continuous exercise, three times per week, increasing gradually to daily 30-minute sessions and if they any questions we advise them to talk to their midwife or GP.”
The study is published in BJOG: an International Journal of Obstetrics and Gynaecology.