Pregnancy-related cardiac outcomes among patients with congenital heart disease after formalization of a cardio-obstetrics program.

Background: The prevalence of pregnant patients with congenital heart disease (CHD) is increasing, and these patients are at high risk for cardiac morbidity.
Objective: This study aimed to examine the pregnancy outcomes in patients with congenital heart disease before and after the establishment of formal cardio-obstetrics collaboration between adult congenital heart disease and maternal-fetal medicine programs.
Study Design: This was a retrospective cohort study of pregnant patients with congenital heart disease from 2002 to 2020 at a single urban academic institution in the United States. This study included patients with a singleton pregnancy who continued a pregnancy beyond 20 weeks of gestation. The primary outcome was a composite adverse maternal cardiac outcome, compared before (2002-2010) and after (2011-2020) the program. The secondary outcomes included gestational age at delivery, mode of delivery, rate of labor induction, use of diuresis after delivery, and a composite maternal morbidity outcome.
Results: The number of pregnant patients with congenital heart disease increased after formalization of the cardio-obstetrics program (200 [postprogram group] vs 84 [preprogram group]; 0.48% of all deliveries in the postprogram group vs 0.25% of all deliveries in the preprogram group; P<.001). The postprogram group was more likely to undergo labor induction than the preprogram group (126 [63%] vs 34 [41%], respectively; P<.001). There were fewer patients in the postprogram group than in the preprogram group who were New York Heart Association class II to IV (23 [12%] vs 17 [22%], respectively; P=.04) or with systemic ventricular dysfunction (8 [4%] vs 12 [16%], respectively; P=.001). There was no difference in the primary outcome (38 [19%] in the postprogram group vs 14 [17%] in the preprogram group; P=.64), even after adjusting for confounders, including New York Heart Association class >I and systemic ventricular dysfunction (adjusted odds ratio, 2.3; 95% confidence interval, 0.96-5.4). Patients in the postprogram group were more likely to receive diuresis after delivery than patients in the preprogram group, even in the absence of heart failure or pulmonary edema (9 [4.5%] vs 0 [0.0%], respectively; P=.04).
Conclusion: In the period after the establishment of a formal cardio-obstetrics program between adult congenital heart disease and maternal-fetal medicine, the number of patients with congenital heart disease delivering at our institution increased significantly. Overall, fewer patients entered pregnancy with advanced-stage heart failure or systemic ventricular dysfunction, possibly suggesting improved prepregnancy cardiac care or improved preconception counseling. Composite maternal cardiac outcomes were similar, but the rates of postpartum diuresis increased significantly, suggesting increased attention to volume status in the postpartum period. Formalized collaboration between congenital heart disease and maternal-fetal medicine may help better optimize patients' care before conception, during pregnancy, and after delivery.
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