Adverse pregnancy outcomes in hypertensive disorders of pregnancy: an in-depth comparison between subtypes.

Objective: To compare adverse pregnancy outcomes (APOs) between subtypes of hypertensive disorders of pregnancy (HDP). Methods: Data were obtained from the Maternal Near-Miss Surveillance System in Hunan Province, China, 2012-2022. HDP was classified into four subtypes: preeclampsia-eclampsia (PE), chronic hypertension (CH), chronic hypertension with superimposed preeclampsia (CHSP), and gestational hypertension (GH). Pearson's chi-square tests were used to determine if there were significant differences in the prevalence of APOs between HDP subtypes. Results: A total of 780,359 pregnant women were included, and 38,397 HDPs were identified, including 17,782 PEs (46.31%), 15,889 GHs (41.38%), 3,340 CHs (8.70%), and 1,386 CHSPs (3.61%). The overall prevalence of APOs among pregnant women with HDP was as follows: anemia (30.78%), diabetes mellitus (20.33%), preterm birth (19.53%), low birthweight (18.74%), hemorrhage disorder (9.07%), infection (4.71%), liver disease (2.55%), stillbirth and neonatal death (2.38%), maternal near-miss (1.57%), kidney disease (0.98%), heart disease (0.65%), pulmonary disease (0.11%), embolism (0.03%), and maternal death (0.02%). There were significant differences in the prevalence of all APOs between HDP subtypes, except for pulmonary disease, embolism, and maternal death ( Conclusion: Most APOs were more common in both CHSP and PE than other subtypes, including preterm birth, low birthweight, infection, stillbirth and neonatal death, and maternal near-miss; diabetes mellitus, liver disease, kidney disease, and heart disease were common in CHSP but not PE; anemia and hemorrhage disorder were common in PE but not CHSP; diabetes mellitus, kidney disease and heart disease were common in CH. Our finding is useful for clinical counseling and future in-depth studies.