The relative importance of gestational gain and maternal characteristics associated with the risk of becoming overweight after pregnancy

OBJECTIVES: To assess the relationships between gestational gain, race/ethn icity, reproductive history, age, education and the risk of becoming overwe ight after pregnancy. STUDY DESIGN: Prospective cohort study of adult women from four race/ethnic ity groups who had two consecutive births between 1980 and 1990 at the Univ ersity of California, San Francisco (UCSF). MEASUREMENTS: Height and pregravid weights for each pregnancy were self-rep orted. Women were classified as overweight or not overweight according to t he Institute of Medicine (IOM) criteria for pregnancy. Gestational gain was defined as the difference between the pregravid weight and the last weight before delivery of the first study pregnancy. SUBJECTS: 1300 healthy women aged 18-41 y who had a singleton, full-term, l ive birth (index or first study pregnancy) followed by a second birth. Self -reported pregravid weights and heights were used to calculate body mass in dex (BMI). Women with a pregravid BMI below 26.0 kg/m(2) before the index p regnancy were classified as not overweight (n = 1128). Overweight status fo llowing the index pregnancy was based on pregravid BMI for the second pregn ancy. RESULTS: Seventy-two women (6.4%) became overweight following the index pre gnancy. Statistically significant independent predictors of the risk of bec oming overweight included: maternal age 24-30 vs above 30 y, high gestation al gain, short interval from menarche to first ever birth (< 8 y), and youn g age at menarche (< 12 y). The risk of becoming overweight was increased 2 .5-3 times for each of these risk factors. Whites were 4.5 times more likel y to become overweight than Asians, but blacks and Hispanics did not appear to differ from whites. Parity, time interval, smoking habit, education, ma rital status and other factors were not associated with the risk of becomin g overweight. CONCLUSIONS: These findings suggest that young age at menarche, maternal ag e and short time from menarche to first ever birth may be as important as h igh gestational weight gain in determining the risk of becoming overweight after pregnancy.