Blood pressure patterns of gestational hypertension or non-severe pre-eclampsia beyond 36 weeks’ gestation and the adverse maternal outcomes: Secondary analysis of the HYPITAT study

Objectives: To identify patterns in changes of blood pressure for women with gestational hypertension (GH) or non-severe pre-eclampsia (PE) beyond 36 gestational weeks, and assess their association with a composite adverse maternal outcome. Study design: Secondary analysis of a randomized controlled trial (HYPITAT). Main outcome measures: We investigated patterns of one-week blood pressure changes post-admission, explored factors contributing to diverse patterns using ANOVA and Chi-square tests, and assessed the correlation between these patterns and a composite adverse maternal outcome defined as severe maternal morbidity, mortality, post-partum hemorrhage and cesarean section. Among 384 women, 187 developed the composite outcome. Results: We identified three and four typical patterns in systolic and diastolic blood pressure changes, respectively. Diastolic blood pressure patterns statistically significantly varied across maternal ethnicity and diagnosis at admission. Compared to a pattern of steady diastolic blood pressure, the odds ratio (95 % confidence interval) for the composite adverse maternal outcome was 2.59 (1.31, 5.13) or 2.09 (1.02, 4.26), contingent on covariates, when a pattern of increasing diastolic blood pressure was present. The results of sensitivity analysis excluding severe hypertension from the composite outcome indicated that the main findings are robust. Conclusions: Maternal ethnicity and diagnosis may affect diastolic blood pressure patterns, and a pattern of increasing diastolic blood pressure was likely associated with elevated risk of the composite adverse maternal outcome. This underscores the potential significance of recognizing these patterns for sequential risk assessment and individualized management in late GH and non-severe PE.