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Weight loss during pregnancy helps mom and baby

Pregnant women who are overweight and obese can safely reduce their weight by eating a healthy diet to reduce the risks of complications for themselves and their baby.

Pregnant women who are overweight and obese can safely reduce their weight by eating a healthy diet to reduce the risks of complications for themselves and the baby.

Nearly 58 per cent of women in Ontario exceeded guidelines for weight gain during pregnancy in a study published last month. Excessive weight gain during pregnancy is associated with health problems such as heart and metabolic complications.

Diets reduced gestational weight gain more than physical activity, researchers found. (iStock)

In Thursday's online issue of the British Medical Journal, researchers analyzed the results of randomized trials of diet and physical activity plans for weight management in more than 7,000 women.

"Dietary intervention is effective, safe and potentially cost effective and dominates physical activity based intervention," Dr. Shakila Thangaratinam, from Queen Mary, University of London, and her co-authors concluded.

Diets reduced gestational weight gain the most, by four kilograms on average, compared with 0.7 kilograms with physical activity and 1.0 kilogram for a mixed approach, they said.

"One of the main concerns of the mothers is the effect of dietary and lifestyle interventions on the weight of the fetus. There is no evidence that the interventions evaluated in our review or recommended in current clinical practice are associated with adverse maternal or fetal outcomes."

The diet plans that reduced weight gain in pregnancy were nutritionally balanced including:

  • Unprocessed whole grains, fruits, beans and vegetables.
  • A maximum of 30 per cent fat, 15 to 20 per cent protein and 50 to 55 per cent carbohydrate.

The energy intake should be individualized to the needs of the mother, the authors advised.

The authors speculated that the mixed diet and physical activity approaches might not have worked as well because compliance suffered or because diet is perceived as safer in pregnancy.

Obesity in pregnant women increases the risk of delivery by C-section or with instruments, hemorrhage, infection , longer hospital stay and need for neonatal intensive care, a journal editorial accompanying the paper said.

Lucilla Poston and Lucy Chappell of St Thomas' Hospital in London called the review "timely and welcome," but said there is not yet sufficient evidence to support diet or other interventions in pregnancy.

Randomized clinical trials, the gold standard in medical research, are underway in the U.K. and Australia to assess elements of intervention in overweight and pregnant women.

"This should also enable data on safety to be obtained from the trials themselves rather than relying on other, less appropriate, assessments of adverse outcomes obtained from observational studies in very different populations (such as women who are pregnant during war or famine)," they concluded.

The study was funded by the U.K. National Institute for Health.

Poston and Chappell said the study does not provide the evidence needed to reassess the guidelines for weight management in pregnancy.

They said several ongoing trials will enable a greater understanding of effective interventions in overweight and obese women.