Healthy diet during pregnancy reduces need for c-section

20 Jul 2017 --- Pregnant women who have a healthy diet and regularly engage in moderate exercise are less likely to have a caesarean section, gain excessive weight or develop diabetes in pregnancy, according to the results of a study led by Queen Mary University of London (QMUL) that used data from over 12,000 women.

The study, published in the BMJ, involved more than 50 researchers from 41 institutions, making it the largest research project in the world that has looked at lifestyle interventions in pregnancy. Its results were recently used by the UK Chief Medical Officers in the Department of Health’s infographics on physical activity in pregnancy, which recommended at least 150 minutes of moderately intense activity every week.

The QMUL study looked at the individual participant data for 12,526 pregnant women across 36 previous trials in 16 countries. These trials compared the effects of dieting (including, for example, the restriction of sugar-sweetened beverages) and physical activity (moderate intensity including aerobic classes, stationary cycling and resistance training for muscle groups).

Combining dieting with physical activity reduced the mother’s weight gain by a significant amount during pregnancy, by an average of 0.7 kg compared to the control group. It also lowered the odds of the mother having a caesarean section by about 10 percent. UK caesarean rates are around 25 percent and can carry risks such as infections for the mother and breathing difficulties for the baby.

According to previous studies, diet and physical activity help with limiting weight gain during pregnancy overall, but the protective effect on outcomes for mothers and their offspring has varied in findings. Half of all women of childbearing age worldwide are at risk in pregnancy and later life due to being overweight or obese.

Professor Shakila Thangaratinam from QMUL’s Barts Research Centre for Women's Health says, “Our findings are important because it is often thought that pregnant women shouldn’t exercise because it may harm the baby. But we show that the babies are not affected by physical activity or dieting, and that there are additional benefits including a reduction in maternal weight gain, diabetes in pregnancy, and the risk of requiring a caesarean section.”

“This should be part of routine advice in pregnancy, given by practitioners as well as midwives. Now that we’re able to link the advice to why it’s beneficial for mothers-to-be, we hope mothers are more likely to adopt these lifestyle changes.”

Professor Thangaratinam says, “For every 40 mothers who follow the healthy diet and moderate exercise, one less woman will end up with a caesarean section.”

Changes in lifestyle reduced the risk of diabetes in pregnancy by 24 percent, which normally affects over one in 10 pregnant mothers and increases risks of complications in mother and baby.

In the UK, only obese women are currently offered access to a dietician and specific antenatal classes for advice on diet and lifestyle.

Professor Thangaratinam adds, “Often with interventions like these, certain groups benefit more than others, but we’ve shown that diet and physical activity has a beneficial effect across all groups, irrespective of your body mass index (BMI), age or ethnicity. These interventions have the potential to benefit a huge number of people.”

There was no strong evidence that the interventions affected offspring outcomes such as stillbirth, underweight or overweight births, or admission to a neonatal intensive care unit. The lack of adverse effects should reassure mothers who have traditionally been advised not to undertake structured exercise or manage their diet in pregnancy.

The study is limited in that the researchers were only able to broadly classify the ethnicity of women as Caucasian or non-Caucasian, and the vast majority of the population in the study had a medium-to-high education, a factor favoring compliance with interventions. It was funded by The National Institute for Health Research (NIHR) Health Technology Assessment (HTA) program.