Weight Change Between Pregnancies 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 (CPP), U.S., 1959–1966, with vital status follow-up through 2016, we used interconception weight change (ICWC) and interpregnancy weight change (IPWC) as proxies of PPWR. ICWC was defined as the difference between self-reported pre-pregnancy weight from the 1st and 2nd CPP pregnancies, while IPWC was the difference between weight recorded at delivery of the 1st and pre-pregnancy 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 ICWC > 0 to 1.8 kg (quintile 3), those with ICWC > −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 IPWC (i.e., greater weight loss) were suggestive of reduced all-cause and cause-specific risk of mortality, though the estimates were not statistically significant. Conclusions: Minimizing PPWR was linked to reduced mortality risk over 50 years of follow-up.