new mum and babyPregnant women can minimise the risks of complications during pregnancy by maintaining a healthy weight through a healthy diet and exercise, an updated review in the Cochrane Library has said.

Research that gaining too much weight – often labelled as “eating for two” – increases the risk of gestational diabetes, high blood pressure and delivery by caesarean section. It may also lead to large babies, which in turn can result in childhood obesity.

The original review, published in 2012, found inconclusive evidence that a healthy diet and regular exercise was beneficial for pregnant women and their babies. However, there is now a growing body of evidence to support the claims, after the research team included evidence from nearly 40 studies published between October 2011 and November 2014. This means the sample size of women is almost 11,500.

The researchers found that about 36% of women who received support to help them manage their weight had excessive weight gain over the course of their pregnancy compared with around 45% in the control groups. The interventions offered as support involved low sugar diets, exercise only, or diet and exercise combined. All interventions led to similar reductions in the number of women gaining excessive weight. Exercise was mainly of moderate intensity and included a number of different individual or group activities such as walking, aerobics and dance.

Additionally, women receiving the interventions were less likely to have high blood pressure. It was also found that the interventions may lead to a small reduction in caesarean deliveries, down from 29% to 27%, as well as reducing the chance of having a baby with a large birthweight.

However, the reviewers were unable to determine whether supervised interventions were better than counselling interventions. It is hoped data from several ongoing trials will answer this question in the future.

“The review’s findings will be important for informing antenatal care guidelines,” said lead author Benja Muktabhant, an Associate Professor in the Department of Nutrition at Khon Kaen University, in Thailand. “However, we need more studies on the effectiveness of these interventions in low-income countries and in women with non-Western lifestyles.”

A new World Health Organization guideline on antenatal care is in development and is expected to include recommendations based on this evidence.

“Pregnancy is a time when women have a lot of contact with healthcare providers, therefore there is no better time to engage and support women to make healthy lifestyle choices,” said co-author Tess Lawrie. “We hope that these findings will encourage women not to overeat and to exercise regularly with the knowledge that their efforts will be rewarded with lower pregnancy weight gain and better health outcomes for themselves and their baby.”

Pregnant women should refer to the Royal College of Obstetricians and Gynaecologists guidelines on exercise in pregnancy, and that before embarking on a new exercise program they should discuss it with their midwife or doctor, the researchers said.