Abstract Body (Do not enter title and authors here): Background:
Hypertensive disorders of pregnancy (HDP) are among the primary reasons for maternal and perinatal deaths globally. Encompassing chronic hypertension, pregnancy induced hypertension (PIH), and preeclampsia, HDP are among the most frequent complications encountered during pregnancy. Considering the emerging congenital heart disease (CHD) population globally, research on HDP in pregnancies with CHD is urgently needed.

Methods:
Outcomes for 2220 pregnant women with CHD were evaluated retrospectively from 1993 to 2016 and prospectively from 2017 to 2019 from 7 tertiary hospitals. Maternal death, cardiac complications, obstetric and offspring complications of completed pregnancies and their demographics, cardiac characteristics, and comorbidities were collected. To identify the risk factors for HDP, univariate and multivariate analysis were performed through logistic regression.

Results:
Of 2220 completed pregnancies with CHD from 7 tertiary institutions, 77 women had PIH, and 76 women had preeclampsia. The main CHD diagnosis of patients with PIH was shunt lesion (including ASD, VSD, and PDA), left heart abnormality (including AS/AI, BAV, and COA), and single ventricle (SV). The main CHD diagnosis of patients with preeclampsia was shunt lesion (including ASD, VSD, and PDA), left heart abnormality (including AS/AI and MS/MI), and right heart abnormality (including TOF, PS/PAS/PI, DORV and DCRV).
In parturients with PIH, the mortality and incidence of heart failure were 2.60% and 15.58%, respectively. In parturients with preeclampsia, the mortality and incidence of heart failure were 6.58% and 23.68%, respectively. Pregnancies with HDP had a significantly higher incidence of adverse maternal and offspring events than pregnancies without HDP.
Independent risk factors for HDP included multiple gestation, use of medically assisted reproduction, having elevated brain natriuretic peptide (BNP) level, delayed first ANC visit, and absence of strict antenatal supervision.

Conclusion:
In summary, the presence of HDP in women with CHD significantly increased the risk of mortality and morbidity for both the mother and the child, particularly in cases involving preeclampsia.