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Exercise, dieting in pregnancy lowers risk for diabetes, weight gain, C-section

Pregnant women who adhere to interventions based on healthy diet and moderate physical activity are less likely to develop gestational diabetes, gain excess weight or have a cesarean section, according to a new study.

“Half of all women of childbearing age worldwide are overweight or obese,” the International Weight Management in Pregnancy Collaborative Group, wrote in BMJ. “Obesity and excessive gestational weight gain put mother and offspring at risk, both in pregnancy and in later life. The resultant costs to the health service and society are considerable.”

“Syntheses of study level data on effects of diet and physical activity based interventions in pregnancy have shown an overall benefit on limiting gestational weight gain, but the findings varied for their protective effect on maternal and offspring outcomes,” they added.

The researchers conducted a systematic review and meta-analysis of individual participant data from 36 randomized trials (n = 12,526) to determine how diet and physical activity interventions during pregnancy affect gestational weight gain and maternal and offspring composite outcomes. Diet and physical activity interventions included access to a dietician, specific antenatal classes for advice on diet and lifestyle or structured exercise of moderate intensity, such as aerobic classes, stationary cycling and resistance training for muscle groups. Dieting included restriction of sugar sweetened beverages, promotion of low-fat dairy products and increased consumption of fruits and vegetables.

Data indicated that compared with the control group, the intervention group experienced less weight gain (mean difference = 0.7 kg; 95% CI, 0.92 to 0.48 kg; 33 studies; n = 9,320). Diet and physical activity also decreased the likelihood of the mother having a cesarean section by approximately 10%. The risk for diabetes during pregnancy was reduced by 24% as a result of lifestyle changes.

The odds of adverse maternal (OR = 0.9; 95% CI, 0.79-1.03; 24 studies; n = 8,852) and offspring (OR = 0.94; 95% CI, 0.83-1.08; 18 studies; n = 7,981) composite outcomes with diet and physical activity were reduced, but the difference was not statistically significant and did not vary across subgroups of women categorized by age, parity, BMI, ethnicity and preexisting medical conditions. Strong evidence from individual participant data demonstrated a significant reduction of cesarean section incidence in the intervention group (OR = 0.91; 95% CI, 0.83-0.99; 32 studies; n = 11,410); however, this was not seen for other individual complications. The overall effect of interventions was similar, whereas the benefits for gestational diabetes were stronger (OR = 0.76; 95% CI, 0.65-0.89; 59 studies; n = 16,885) when the researchers supplemented individual participant data with evidence from studies that did not provide individual participant data.

Adverse outcomes for offspring, including stillbirth, underweight or overweight births or admission to a neonatal intensive care unit, were not affected by the interventions.

“Our findings are important because it is often thought that pregnant women shouldn't exercise because it may harm the baby,” Shakila Thangaratinam, PhD, from Queen Mary University of London’s Barts Research Center for Women’s Health, said in a related press release. “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 cesarean section.”

“This should be part of routine advice in pregnancy, given by practitioners as well as midwives,” she added. “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.”

“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 BMI, age or ethnicity; so these interventions have the potential to benefit a huge number of people,” she said. – by Alaina Tedesco

Disclosure: All authors report no relevant financial disclosures.