Time trends and birth rates in women with congenital heart disease; a nationwide cohort study from Norway 1994-2014.

Background: More women with congenital heart disease (CHD) reach reproductive age, but little is known of their success in having children. We investigated time trends of CHD in women of reproductive age and maternal CHD in childbirth and compared birth rates in women with CHD to birth rates in women without heart disease. Methods and results: In a national cohort, we combined information from five registries in Norway 1994-2014. Among 1,644,650 women aged 15-45 years, 5672 had CHD. Among 1,183,851 childbirths, 3504 were registered with maternal CHD. The prevalences of mild and moderate/severe CHD in women increased by an average of 3-4% per year 1994-2014, as did the prevalences of mild and moderate/severe maternal CHD in childbirth. Compared to women without heart disease, the likelihood of having children was similar for women with mild CHD (rate ratio 1.03, 95% confidence interval 0.97-1.09) but lower for women with moderate/severe CHD (rate ratio 0.75, 95% confidence interval 0.68-0.84). The mean number of childbirths was similar in women with mild CHD and women without heart disease (1.81 vs 1.80, p = 0.722) but lower in women with moderate/severe CHD (1.42, p < 0.001). Conclusion: In a national cohort over two decades of women of reproductive age, the prevalence of maternal CHD in childbirth reflected the increasing prevalence of CHD in the population. Birth rates were similar for women with mild CHD and women without heart disease, whereas women with moderate/severe CHD were less likely to have children and had a lower mean number of childbirths.