Moderate exercise during pregnancy reduces a woman's risk of having a large baby, which also reduces the need for a caesarean section, a new study indicates.

Spanish scientists monitored the progress of over 500 pregnant women. At the beginning of the study, all were considered sedentary - in other words, they were exercising for less than 20 minutes per day, less than three days a week.

The women were divided into two groups. One group received the standard care and recommendations, while the other group also followed an exercise programme. This was made up of 55-minute sessions of aerobic, flexibility and muscle strength exercises, three days per week.

The exercise group undertook these sessions from 10-12 weeks of pregnancy to 38-39 weeks.

The study found that the risk of gestational diabetes did not fall among the exercise group, however, the risk of macrosomia did. Macrosomia refers to babies who are considered abnormally large before birth. They have a birth weight of at least four kilos (8lbs, 13ozs).

Overall, women who undertook the moderate-intensity exercise programme three times a week during the second and third trimesters of their pregnancy reduced their risk of macrosomia by 58%.

Having a larger baby increases the risk of requiring a caesarean section, therefore the risk of needing a section also fell by 34% among the women who exercised.

According to the scientists, this study ‘reinforces the need to encourage more supervised exercise interventions during pregnancy'.

Details of these findings are published in the British Journal of Sports Medicine.

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