Longitudinal blood pressure trajectories before 20 weeks of gestation and adverse outcomes in women with chronic hypertension

OBJECTIVE: To explore the different patterns in early-pregnancy mean arterial pressure (MAP) trajectories before 20 weeks of gestation in pregnant women with chronic hypertension, and whether it can stratify risk for adverse perinatal outcomes. METHODS: We conducted a retrospective cohort study of pregnant women with chronic hypertension who were hospitalized at Peking University Third Hospital between January 2018 and November 2024. By longitudinal trajectory clustering of MAP measurements obtained before 20 weeks of gestation, we identified distinct blood pressure trajectory groups. Multivariable regression models were used to evaluate associations with pregnancy outcomes. RESULTS: Two MAP trajectory groups were identified. The low trajectory group started around 95 mmHg (≈130/80 mmHg) and remained below this level for most of gestation, whereas the high trajectory group started around 105 mmHg (≈140/90 mmHg) and remained above 95 mmHg thereafter. After full adjustment, the high trajectory group had higher rates of composite adverse outcomes than the low trajectory group (21.8% vs. 13.6%; adjusted odds ratio [aOR] 1.494, 95% confidence interval [CI]: 1.059-2.106), shorter gestational age at delivery (B - 0.369 weeks, 95% CI: -0.716 to -0.022), and lower neonatal birth weight (B - 106.065 g, 95% CI: -187.118 to -25.012). CONCLUSION: Early-pregnancy MAP trajectory patterns derived from routine measurements before 20 weeks of gestation provide clinically useful risk stratification in pregnancies complicated by chronic hypertension. These findings indicate that active blood pressure management before 20 weeks is associated with improved perinatal outcomes, underscoring the importance of early and active intervention in pregnant women with chronic hypertension.