Dieters Gain More Weight During Pregnancy
Women who have a history of dieting are more likely to experience excessive weight gain during pregnancy, a new study shows.

Researchers from the University of North Carolina at Chapel Hill questioned 1,200 women about their dieting history, weight and weight gain during pregnancy. Recommendations for normal weight gain during pregnancy vary depending on a woman’s size. A woman who is underweight is encouraged to gain 28 to 40 pounds. Normal-weight women should gain between 25 and 35 pounds. Women who are overweight or obese are advised to limit weight gain to 15 to 25 pounds.

Most women with a history of dieting were more likely to exceed weight gain recommendations, regardless of their pre-pregnancy weight. The exception was women who were underweight before pregnancy. Underweight women who had a history of dieting did not gain enough weight, compared to underweight women who weren’t typically restrained eaters. The findings were published this month in The Journal of the American Dietetic Association.

Co-author Anna Maria Siega-Riz said the findings show that women with a history of unhealthy eating behaviors should be offered counseling and extra support to help them achieve a healthy weight during pregnancy.

In the past, doctors have primarily been concerned with underweight women not gaining enough weight during pregnancy. But the rising prevalence of overweight and obesity has shifted the focus to the effects of excess weight gain. Excess weight gain increases risk for Caesarean sections, having a large baby, shorter duration of breast-feeding and a more difficult time losing weight after delivery. Some studies suggest excess weight gain during pregnancy can also affect the lifelong health of both mother and baby.

In June The American Journal of Clinical Nutrition reported that children of mothers who gain more than the recommended amount of weight during pregnancy are more likely to be overweight at age 7 years.

“The earliest determinants of obesity may operate during intrauterine life, and gestational weight gain may influence the environment in the womb in ways that can have long-term consequences on the risk of obesity in children,” said Brian Wrotniak, the study’s lead author, from the Children’s Hospital of Philadelphia and the University of Pennsylvania.

Significant weight gain during pregnancy also may cause changes in breast tissue that increase susceptibility to breast cancer in later life.