Postpartum Weight Retention and Mortality Over 50 Years of Follow-up

Objective: This study aimed to evaluate the link between postpartum weight retention (PPWR) and long-term mortality. Methods: In this secondary analysis of 8165 women with ≥2 pregnancies in the Collaborative Perinatal Project (U.S., 1959–1966) with vital status follow-up through 2016, we used interpregnancy weight change (IPWC) and postpartum weight change (PPWC) as proxies of PPWR. IPWC was defined as the difference between self–reported pre–pregnancy weights from the 1st and 2nd CPP pregnancies, while PPWC was the difference between weight recorded at delivery of the 1st and prepregnancy weight of the 2nd CPP pregnancies. All–cause and cause–specific mortality models were adjusted for sociodemographic, behavioral, clinical, and pregnancy related characteristics from the 1st CPP pregnancy. Results: Compared to women with IPWC >0 to 1.8 kg (quintile 3), those with IPWC > −1.4 to 0 kg (quintile 2) had a lower risk of all-cause mortality [aHR (95% CI): 0.85 (0.76–0.96)], with the most notable reduction observed in diabetes-related risk of mortality [aHR (95% CI): 0.45 (0.23–0.87)]. Lower quintiles of PPWC (i.e., greater weight loss) were linked to reduced all–cause and cause–specific risk of mortality, though estimates were imprecise. Conclusions: Modest PPWR was linked with increased mortality risk over 50 years of follow-up.