Long-term weight development in women: a 15-year follow-up of the effects of pregnancy

Objective: The aim of this study was to evaluate how well prepregnancy BMI, gestational weight gain, and postpartum weight retention predict retention of weight 15 years later among parous women.

Research methods and procedures: The Stockholm Pregnancy and Women's Nutrition (SPAWN) study is a long-term follow-up study of women who delivered children in 1984 to 1985 (n = 2342). The participants initially filled out questionnaires about their eating and exercise habits, social circumstances, etc. before, during, and at 1 year after pregnancy. Anthropometric data were also sampled. Fifteen years later, these women were invited to take part in the follow-up study. Anthropometric measurements were collected, and similar questions were asked. Five hundred sixty-three women participated in the SPAWN 15-year follow-up study. The sample was divided into groups to examine three presumably critical time periods: 1) overweight and normal weight before pregnancy; 2) low, intermediate, and high weight gainers during pregnancy; and 3) low, intermediate, and high weight retainers at 1 year after pregnancy.

Results: The overweight women did not gain more weight during pregnancy or retain more weight at 1 year follow-up. High weight gainers during pregnancy retained more weight at the 1-year and the 15-year follow-ups. High weight retainers had gained more during pregnancy and retained it at the 15-year follow-up. Fifty-six percent of the high weight gainers during pregnancy ended up in the high weight retainers group.

Discussion: Women who are overweight before pregnancy do not have a higher risk of postpartum weight retention than normal weight women. Thus, it is not necessarily the initially overweight woman who should be the target or focus of weight control programs during or after pregnancy. Both high weight gainers and high weight retainers had higher BMI at the 15-year follow-up, although only 56% of the high weight gainers during pregnancy were also classified as high weight retainers at the 1-year follow-up. Weight retention at the end of the postpartum year predicts future overweight 15 years later.