Premature Births Linked to Dieting

Don’t diet before becoming pregnant. That’s the warning from an international team of scientists who suggest that even modest restrictions in a woman’s nutritional intake around the time of conception can lead to premature birth and long-term health problems in children.

“This period of undernutrition could have an impact on the development of the pituitary and adrenal glands of the baby and may well affect the development of other organ systems,” says Dr. John Challis, a professor of medicine and physiology, U of T’s vice-president (research) and associate provost, and a senior author of the study, published in Science. “Do not diet substantially before the start of pregnancy because it’s not necessarily a good thing for your pregnancy, and you may cause your baby to be born prematurely.”

In a study of about 40 sheep, researchers maintained a fully nourished control group and an experimental group in which the ewes were underfed, leading to a weight loss of about 15 per cent. Nutrition was restricted 60 days prior to mating and 30 days after conception. The researchers found that, on average, undernourished ewes delivered prematurely by one week. Some ewes were up to 20 days early. “Even after adequate nutrition is reintroduced, months later there’s been an effect on the fetus,” says lead author Dr. Frank Bloomfield of the University of Auckland, who conducted the research, with Challis, while a post-doctoral fellow at U of T.