Weight Fluctuations from Pregnancy Until 3 Years Postpartum: Timing and Goals for Women’s Weight Management

Background: The prevalence of being overweight and of obesity among women of childbearing age is constantly increasing. Objectives: To analyze the critical periods and goals of women’s weight management from early pregnancy to 3 years postpartum. Methods: Women’s weight was tracked from the first trimester of pregnancy to 3 years postpartum. We calculated their gestational weight gain (GWG) and postpartum weight retention (PPWR), and used linear mixed models and logistic models to estimate weight change velocities and risk factors associated with overweight/obesity at 1–3 years postpartum. Results: The medians of pre-pregnancy BMI (pre-BMI) and GWG among the 641 participants were 20.1 kg/m2 and 15.0 kg. Among women with pre-BMI < 24 kg/m2, those with excessive GWG remained at higher weights within 1.5 years postpartum than those with appropriate GWG (p < 0.05). Women’s weight decreased from 42 days to 1 year postpartum (β = −0.31 for low pre-BMI, β = −0.24 for normal pre-BMI, both p < 0.05), and remained unchanged from 1 to 3 years (p > 0.05). The rate of being overweight/obese at one year postpartum was mainly associated with pre-pregnancy weight (as a continuous variable, aOR = 1.58, 95%CI: 1.44–1.74) and 1-year PPWR (aOR = 1.78, 95%CI: 1.48–2.15). Compared with women who maintained normal BMI, those who shifted to being overweight/obese had higher pre-BMI and 1-year PPWR (22.6 kg/m2 vs. 20.3 kg/m2, 7.0 kg vs. 1.0 kg, p < 0.01). Conclusions: Normal and relatively low pre-BMI (18.5–22.0 kg/m2) and less than 2.0 kg of 1-year PPWR are goals of women’s weight management.