Data Source and Study Population We enrolled patients from seven main medical centers in Southwestern China,that was used to characterize outcomes from December 1, 2010 to December 31, 2019. All pregnant women (excluding abortion, nonfirst delivery, multiple births) were eligible for inclusion in the present analysis. Cardiac disease of pregnant woman in the analysis mainly included valvular heart disease (VHD), cardiomyopathy, adult congenital heart disease (ACHD), pulmonary hypertension (PH) and other cardiac conditions (primary arrythmia, coronary heart disease, anemic heart disease, hyperthyroid heart disease and others). Only singleton records with a unique medical identified number were used in our analysis. Patients aged \<18 years and those with missing information including unique patient identifiers were excluded. Records with the same date of birth, admission date, discharge date, and facility name were considered as pure duplications, and only one of such records was kept. The data set was analyzed retrospectively, and the informed consent requirement was waived.
Outcome Measures Hypertensive disorders of pregnancy were defined and classified mainly as the following two types from ISSHP (International Society for the Study of Hypertension in Pregnancy) Classification, Diagnosis, and Management Recommendations for International Practice: Hypertension known before pregnancy or present in the first 20 weeks; Hypertension arising de novo at or after 20 weeks.\[10\] Maternal major adverse cardiac events (MACE) were defined as a composite of arrhythmia, shock, cerebrovascular events, heart failure, respiratory failure, in-hospital death, pulmonary embolism, dissection of any artery.\[3, 11, 12\] Cardiac procedural intervention was also recorded for patients with and without HD. Non-MACE maternal outcomes included acute renal failure, total hospital charges and hypertensive disorders of pregnancy (all types). Obstetric complications mainly included adherent placenta, abruptio placenta, breech delivery, DIC (disseminated intravascular coagulation), early or threatened labor, known or suspected fetal abnormality, laceration, long labor, placental insufficiency, placenta previa, precipitate labor, premature rupture of membranes, polyhydramnios, postpartum hemorrhage and infection. Neonatal adverse clinical events (NACE) were a composite of fetal death (in utero), neonate death (within 30 days of birth), prematurity (\<37 weeks), intrauterine growth restriction, respiratory distress syndrome and intracranial cerebral events. NON-MACE variables including infant of low-birth weight (weight\<2500g) and fetal macrosomia (weight\>4000g) were also measured. HF was defined in these patients with various underlying heart diseases as a clinical syndrome that was characterized by specific symptoms (dyspnea and fatigue) and signs (of fluid retention, such as edema, rales) as judged by the treating cardiologist according to ACC/AHA guidelines.\[13\] Information for the present analysis was obtained through review of the institutional database, into which data had been entered on discharge of each patient.
