Labor onset and delivery mode in women with congenital heart disease-A nationwide cohort study.

Introduction: More women with congenital heart disease (CHD) are pursuing pregnancy. Their cardiac condition may impact the pregnancy and necessitate interventions during childbirth. We aimed to investigate labor onset and delivery mode in women with CHD relative to women without heart disease and explore the time trends of induced labor and cesarean deliveries.

Material And Methods: In a nationwide cohort in Norway from 1994 to 2014, we compared childbirths of women with mild, moderate/severe, or other CHD to childbirths of women without heart disease. Associations between maternal CHD and labor onset and delivery mode were estimated using log-binomial regression. Time trends were assessed using Joinpoint regression.

Results: Among 1 218 452 childbirths, 2425 (20 per 10 000) had mild maternal CHD, 603 (5 per 10 000) moderate/severe maternal CHD, and 522 (4 per 10 000) other maternal CHD. Mild maternal CHD was associated with induced labor (aRR 1.11, 95% CI 1.01-1.22) and cesarean delivery (aRR 1.27, 95% CI 1.18-1.39), and the associations were stronger with moderate/severe CHD (induced labor: aRR 1.34, 95% CI 1.13-1.58; cesarean delivery: aRR 1.80, 95% CI 1.57-2.05) and other CHD (induced labor: aRR 1.39, 95% CI 1.17-1.66; cesarean delivery: aRR 1.62, 95% CI 1.39-1.89). From the first seven years (1994-2000) to the last (2008-2014), the cesarean delivery occurrence rose about 2% per year in childbirths without maternal heart disease and with mild maternal CHD (from 12.4% to 16.4% and from 14.2% to 21.2%, respectively), but remained stable in childbirths with moderate/severe maternal CHD (23.3% to 25.6%). For induced labor, there was a 2% increase per year in childbirths without maternal heart disease, contrasting a 3%-4% increase in those with mild and moderate/severe maternal CHD.

Conclusions: Maternal CHD was associated with higher risks of induced labor and cesarean delivery. From 1994 to 2014, the increase in induced labor was steeper in childbirths of women with CHD than in those of women without heart disease. The occurrence of cesarean deliveries rose in childbirths of women with mild CHD but was stable in childbirths of women with moderate/severe CHD.