Association between adverse pregnancy outcomes and long-term postpartum blood pressure trajectories: a community-based cohort study

Background: Adverse pregnancy outcomes (APOs) increase the future risk of hypertension, but their impact on long-term postpartum blood pressure (BP) trajectories remains unclear. We aimed to characterize these trajectories and compare trajectory membership between women with and without APOs. Methods: This community-based cohort study included 1,346 women with documented deliveries (2004-2020) from the Kailuan Study who underwent at least three postpartum health examinations between 2006 and 2022. APOs included hypertensive disorders of pregnancy (gestational hypertension and preeclampsia/eclampsia), gestational diabetes mellitus, preterm birth, and low birth weight. Generalized additive mixed models were used to characterize longitudinal changes in systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP). Group-based trajectory modeling was applied to identify distinct BP trajectory groups. Multinomial logistic regression with marginal standardization estimated adjusted risk ratio (aRR). Results: During a mean follow-up of 9.2 years, SBP showed a nonlinear increase, with an average slope of 1.13 mmHg/year (95% CI, 0.93-1.33) during the first 6.4 years, followed by slower increases of 0.73 and 0.59 mmHg/year during 6.4-10 and 10-15 years, respectively. DBP showed a near-linear increasing pattern, whereas MAP increased linearly. Three trajectory groups were identified for each BP component. APOs were associated with higher risks of high-level SBP (aRR = 1.64; 95% CI: 1.19-2.66), DBP (aRR = 1.61, 95% CI: 1.24-1.87), and MAP (aRR = 2.11, 95% CI: 1.16-3.64) trajectories compared with membership in the low-level BP trajectory groups. Associations varied across APOs subtypes. GDM and PTB were associated with higher risk of membership in the high-level SBP, DBP, and MAP trajectory groups compared with the corresponding low-level trajectory groups. Conclusion: Different BP components exhibit distinct longitudinal patterns after delivery, APOs are associated with heterogeneous and unfavorable long-term postpartum BP trajectories.