Obstetric outcome in women with adult congenital heart disease: a nationwide cohort

Abstract Background/Introduction Survival rates and healthcare for patients with congenital heart disease have improved, leading to an increase in pregnancies among women of childbearing age with adult congenital heart disease (ACHD). As survival rates continue to rise, new considerations regarding pregnancy and childbirth emerge. Purpose Our aim was to investigate obstetric outcomes in a large, retrospective, national registry study of women with ACHD compared to controls. Methods The study included women over 18 years of age from the Swedish Registry of Congenital Heart Disease. Each case was matched with 10 controls from Statistics Sweden, based on age and country of birth, and all were subsequently linked to the Swedish Medical Birth Register. We included 7,998 pregnancies in women with ACHD and 84,799 in controls during 1973-2020. We classified women with ACHD into mild/moderate and severe congenital heart disease. Results The mean age at delivery for women with ACHD and controls was 28.7(±5.0) and 28.7(±5.1) years, respectively (Table 1). Women with ACHD smoked less, had shorter gestation and higher incidence of delivery by Cesarean section (CS) compared to controls. We found an increased prevalence of chronic kidney disease and hypertension in women with ACHD compared to controls. Regarding preeclampsia, we did not find any differences in incidence of preeclampsia (including eclampsia) in women with ACHD compared to controls. When performing trend analysis for proportions, a larger proportion of women with ACHD underwent CS over time, from 5.7% 1973 to 18.9% 2020, p-value0.001. Similarly, an increasing proportion of controls underwent CS over time, from 5.1% 1973 to 14.8% 2020, p-value0.001 (Figure 1). The likelihood of CS was increased in women with ACHD compared to controls, odds ratio 1.45 (95% CI 1.37-1.54). Compared to controls, women with ACHD had an increased likelihood of giving birth to small-for-gestational-age neonates (SGA), odds radio 1.40, (95% CI 1.23-1.58). The association regarding SGA remained after adjusting for body mass index, age, smoking, comorbid diseases and preeclampsia. Women with ACHD had an increased likelihood of prematurity compared to controls, OR 1.47 (95% CI 1.35-1.59). Likelihood of CS, SGA neonates and prematurity were higher in severe congenital heart disease than mild/moderate congenital heart disease; both compared to controls. Conclusions In this large national population study in women with ACHD we showed an increased likelihood of giving birth prematurely, by CS, and having a SGA neonate compared to matched controls. The likelihood seems even higher in women with severe congenital heart disease. Further efforts should be made to reduce CS that are not medically indicated. Figure 1.