Cardiac and Pregnancy Outcomes of Pregnant Patients With Congenital Heart Disease According to Risk Classification System.

Pregnancy risk assessment for patients with adult congenital heart disease (ACHD) must include physiologic and anatomic impacts. We aimed to determine whether maternal cardiac and pregnancy outcomes vary by disease severity defined according to the following 3 different classifications: ACHD anatomic severity, ACHD physiologic class, and modified World Health Organization (mWHO) class. Cardiac outcomes included a composite of arrhythmia, heart failure, stroke, and thromboembolism. Pregnancy outcomes included a composite of intrauterine growth restriction, preterm birth, preeclampsia, or postpartum hemorrhage. We employed generalized estimating equations to account for multiple pregnancies. Of the 245 pregnancies, 17.1% were preterm and 45.7% were cesarean deliveries. Cardiac hospitalizations occurred in 22.0% and arrhythmias in 12.7%. Cardiac outcomes tended to be more prevalent in people with more severe heart disease. Pregnancy outcomes were U-shaped or less prevalent in people with more severe disease. There was a 2.9-fold increased risk for the composite cardiac outcome for complex anatomy (adjusted incidence rate ratio 2.90, 95% confidence interval 1.08 to 7.81, p = 0.04), a 9.4-fold increased risk for physiologic class C or D (9.37, 1.28 to 68.79, p = 0.03), and a fourfold increased risk for mWHO class III or IV (3.99, 1.53 to 10.40, p = 0.005). There was a lower risk for the composite pregnancy outcome for mWHO class II or II to III (0.54, 0.36 to 0.79, p = 0.002) but no association with anatomy or physiology. In conclusion, physiologic class may be most accurately associated with adverse outcomes and therefore efforts to optimize hemodynamics before pregnancy may help to mitigate the risk.