How Does Medical Nutrition Therapy Affect Weight Gain During Pregnancy? - Brief Article

Nutrition Research Newsletter, Feb, 2001

One of the most important factors associated with infant birth weight is maternal weight gain. The cultural pressure to be thin in the United States may affect the amount of weight a woman is willing to gain during her pregnancy. Adequate nutrition throughout pregnancy is essential in optimizing the infant's health. Dietitians providing prenatal medical nutrition therapy (MNT) may be able to help optimize a woman's nutrition throughout pregnancy.

Researchers performed a study to determine the effect of MNT on the nutrient intake of pregnant women and to determine their attitudes and beliefs concerning pregnancy and weight gain. The subjects were recruited from a population of women receiving obstetrical care at a family medicine residency center where referral for MNT was a standard part of prenatal care. Women were excluded if they had gestational diabetes, hyperemesis gravidarum, or multiple gestation. Thirty-one women, ages 16 to 37 years, participated. A dietitian took anthropometric measurements including height, weight, and wrist circumference. Ideal body weight (IBW), percentage IBW, percentage IBW for gestational age, total energy need, and target weight gain based on gestational age were calculated for all subjects. A four-page assessment questionnaire contained questions concerning demographics, financial status, common gastrointestinal problems, use of prenatal vitamin and mineral supplements, exercise habits and pregnancy knowledge and concerns. The subjects were questioned about food consumption including foods avoided, frequency of restaurant eating, and changes made in food consumption during pregnancy. A 24-hour recall was also obtained at the initial visit and after follow-up MNT sessions with dietitians. Questions regarding attitudes toward pregnancy and weight gain were also addressed. Laboratory data from the subjects' medical charts was obtained including hemoglobin, hematocrit, and blood glucose levels. Subjects had two MNT sessions with dietitians during their pregnancy.

It was determined that 42% of the women were concerned about excessive weight gain during their pregnancies. The low-income group in the study significantly increased their caloric intake after their first MNT session, while the other groups did not.

The researchers emphasize the value of physicians, dietitians, and other health professionals stressing the importance of weight gain with pregnant women early on in the pregnancy. The dietitian can further give recommendations on how to slow or increase weight gains through evaluating an individual's diet.

M. Dundas, A. Yarbro. Nutrient intake and attitudes of pregnant women concerning their weight gain. Top Clin Nutr 16:50-58 (December 2000) [Correspondence: Mary L. Dundas, PhD, RD, FADA, Associate Professor, Department of Health and Nutrition Sciences. Idaho State University, Pocatello, ID].