New study indicates link between weight gains during pregnancy and dieting history

October 1, 2008

Women who have a history of dieting or other restricted eating practices are at risk of gaining an inappropriate amount of weight during pregnancy. In a study published in the October 2008 issue of the Journal of the American Dietetic Association, researchers from the University of North Carolina at Chapel Hill report that restrained eating behaviors prior to pregnancy were associated with weight gains above the Institute of Medicine recommendations for normal, overweight and obese women, and weight gains below the recommendations for underweight women.

Concern over low birth weight and preterm birth led many to focus attention on determinants of inadequate weight gain during pregnancy. However, with the rising prevalence of obesity among women of childbearing age and the high proportion of women who are gaining in excess of recommendations during pregnancy, the paradigm has shifted to a focus on the determinants of excessive weight gain during pregnancy.

Over 1200 women participated in the study, which was designed to determine whether a history of preconception dieting practices and restrained eating were related to higher weight gains in pregnancy, and whether this differed by prepregnancy BMI status. To assess behaviors associated with restrained eating patterns such as a history of dieting, concern about eating too much food and weight fluctuations, women completed a questionnaire that focused on their preconception habits. Women who were more overweight or obese tended to be classified as restrained eaters, dieters or weight cyclers.

The Institute of Medicine suggests that women should gain 28 to 40 lbs, 25 to 35 lbs, 15 to 25 lbs and at least 15 lbs for underweight, normal weight, overweight and obese women, respectively. The study found that restrained eating behaviors were associated with not gaining within the targeted weight gains. Most importantly, the effect of restrained eating on maternal weight gain varied by pre-pregnancy weight status. Restrained eaters and dieters in the normal, overweight and obese categories tended to gain in excess of recommendations, whereas underweight women gained below the recommendations, when compared to women who did not display restrained eating behaviors.

Co-author Anna Maria Siega-Riz, PhD, RD, suggests that the information from this study "could potentially be used by dietitians and health care providers at a preconception care visit or during family planning to identify women at risk for unhealthy eating behaviors. Women who are identified, particularly those who are underweight, should be followed up for potential eating disorders. For women who are not underweight, counseling and extra support could be given on healthy eating behaviors, increasing physical activity levels, and ways to eliminate stress which may increase the consumption of foods in certain social settings or in reaction to life events. During pregnancy it would be useful to target these women with similar nutritional and physical activity strategies in order to avoid excessive weight gain and adverse pregnancy outcomes such as caesarean sections, Macrosomia, and large-for-gestational age (LGA) as well as shorter duration of breastfeeding and higher weight retention in the postpartum period."

Source: Elsevier Health Sciences