Background: Studies examining postpartum retained weight referenced to prepregnant body weight may mask weight gained after 6 weeks postpartum, a potential unrecognized factor contributing to weight increases after pregnancy. Materials and Methods: Using data from a longitudinal study, we examined three weight patterns from 6 weeks to 6 months postpartum (>2.3 kg gain; >2.3 kg loss; and ±2.3 kg as stable weight) in 302 low-income women. Predictor variables included perinatal variables, health habits, and depression risk at 3 and 6 months postpartum. Results: Mean weight changes were weight-gain group: 5.77 kg, standard deviation (SD) = 2.57; weight loss group: -4.79 kg, SD = 2.10; and stable group: 0.05 kg, SD = 1.24. The odds of gaining weight compared with stable weight increased with prepregnant overweight/obesity (adjusted odds ratio [aOR] = 3.22, 95% confidence interval [CI] = 1.74-6.00), and decreased with a first birth (aOR = 0.47, 95% CI = 0.24-0.93). The odds of losing weight increased with excessive gestational weight gain (aOR = 2.40, 95% CI = 1.10-5.21) and depression risk at 6 months (aOR = 2.57, 95% CI = 1.40-4.72), and decreased with prepregnant overweight/obesity (aOR = 0.49, 95% CI = 0.25-0.94). Health habits were not associated with weight gain or loss. Conclusions: Women with high body mass index (BMIs) may need added postpartum care to avoid gaining weight. Weight loss, although welcomed, may be secondary to depression risk. In both cases, low-cost, effective, and targeted care during the extended postpartum period could benefit women's health.
Keywords: body mass index; depression; gestational weight gain; health habits; postpartum weight.