Epidemiology of gestational weight gain and body weight changes after pregnancy.

Abstract

Women are universally concerned about whether pregnancy will have a lasting impact on their body weight. Anecdotal reports and studies of severely obese women have pointed to pregnancy as a cause of their obesity. In a Stockholm obesity clinic, 40-50 percent of women (mean age 47.8 ± 10.7 years) attributed the onset of their obesity to childbearing, and 73 percent reported a retention of 10 kg after pregnancy (1, 2). However, most of the evidence from observational studies about the influence of pregnancy on postpartum body weight does not support these perceptions. For the majority of women, body weight at 6-18 months postpartum is no more than 1-2 kg greater than preconceptional weight (3-9). Yet, at least 14-20 percent of women in national surveys were more than 5 kg heavier by 6-18 months postpartum (3, 4, 6-8). This evidence suggests that pregnancy may substantially increase postpartum body weight for subgroups of women, such as those with high gestational weight gain (6). A more recent study found an increased risk of becoming overweight among women who had a single pregnancy compared with nongravid women (10). Thus, estimates of average body weight change do not reflect the excess weight increases experienced by a sizable number of women; this may be further compounded over subsequent pregnancies and contribute to the development of obesity. Factors suspected of influencing postpartum body weight include gestational weight gain, pregravid weight, race/ethnicity, parity, and lactation. Body weight at conception may be particularly important among race/ethnic groups in which the prevalence of obesity is high (8). Both mean gestational weight gain and prevalence of overweight women in the US population have increased over the past two decades (8, 11-13). It has not been established whether increased gestational weight gain is responsible for part of the increasing