Risk Factors and Outcomes Associated With Hypertensive Disorders of Pregnancy in Maternal Congenital Heart Disease.

Background: Among women with congenital heart disease (CHD), risk factors for hypertensive disorders of pregnancy (HDP) and the association of HDP with adverse outcomes are unknown.

Objectives: The purpose of this study was to identify risk factors for HDP among women with and without CHD and to assess the association of HDP with adverse events.

Methods: This retrospective cohort study included the first live birth for each woman who was pregnant in Alberta, Canada, between January 1, 2005, and December 31, 2018. The prevalence of HDP among women with and without CHD was compared. Multivariable models were used to determine the independent associations between maternal characteristics and HDP and to assess the strength of associations between HDP and CHD with adverse events.

Results: Of the total birth events, 0.6% (N = 2,575) occurred in women with CHD. HDP were more common among women with CHD (11.2% vs 8.1%,  < 0.0001). Chronic hypertension and diabetes mellitus were strongly associated with HDP among women with CHD (adjusted odds ratio [aOR]: 4.56; 95% confidence interval [CI]: 2.95-7.03; and aOR: 3.33; 95% CI: 1.48-7.49, respectively). Coarctation of the aorta was the only CHD lesion independently associated with increased risk for HDP (aOR: 1.76; 95% CI: 1.02-3.02). HDP, as opposed to CHD, was more strongly associated with having a complicated delivery admission, preterm delivery, and small for gestational age infant.

Conclusions: HDP were more common among women with CHD. The strongest risk factors for HDP among women with CHD were acquired. The presence of HDP, rather than CHD, was more strongly associated with certain adverse outcomes.