Pregnancy in women with corrected tetralogy of Fallot: Occurrence and predictors of adverse events

Background: In women with corrected tetralogy of Fallot (ToF), pregnancy is associated with maternal cardiac, obstetric, and offspring complications. Our aim is to investigate the magnitude and determinants of pregnancy outcome in women with corrected ToF. Methods: In this retrospective international multicenter study using 2 congenital heart disease registries, 204 women with corrected ToF were identified. Within this group, 74 women had 157 pregnancies, including 30 miscarriages and 4 terminations of pregnancy. Detailed information on each completed pregnancy (n = 123) was obtained using medical records and supplementary interviews. Results: Cardiovascular events occurred during 10 (8.1%) pregnancies, mainly (supra)ventricular arrhythmias. Obstetric and offspring events occurred in 73 (58.9%) and 42 (33.9%) pregnancies, respectively, including offspring mortality in 8 (6.4%). The most important predictor was use of cardiac medication before pregnancy (odds ratio for cardiac events 11.7, 95% CI 2.2-62.7; odds ratio for offspring events 8.4, 95% CI 1.4-48.6). In pregnancies with cardiovascular events, significantly more small-for-gestational-age children were born (P value < .01). Conclusions: Cardiovascular, obstetric, and offspring events occur frequently during pregnancies in women with ToF. Maternal use of cardiovascular medication is associated with pregnancy outcome, and maternal cardiovascular events during pregnancy are highly associated with offspring events.