ABSTRACTBackground:Tetralogy of Fallot (TOF) is the commonest cyanotic congenital heart defect. When surgicallyrepaired at young age over 90% of patients reach adult age and most women have a desire to become pregnantHowever, pregnancy is associated with up to 50% increase in cardiac output and also associated with an elevatedrisk of arrhythmias and thrombosis. The aim of this study was to describe the outcomes in women with TOF forboth mother and baby and to assess the influence of pregnancy on right ventricular (RV) dimensions.Methods:Within the prospective, international ESC EORP Registry Of Pregnancy And Cardiac disease (ROPAC),we describe the outcomes in 421 women with repaired TOF. Primary outcome was the occurrence of maternalcardiovascular events. Secondary outcomes were obstetric and fetal events and RV dilatation and pulmonaryvalve deterioration.Results:The mean age was 28.8 years and 52.3% were nulliparous. There were no maternal deaths, and heartfailure and ventricular tachyarrhythmias complicated respectively 5% and 2% of pregnancies. Almost half ofwomen underwent a Caesarean section (48%). Fetal mortality was 1%, while no neonatal mortality occurred.Pregnancy induced hypertension and HELLP/(pre)eclampsia were found in 3% and 1% respectively. Pretermdelivery was observed in 14% and 10% had low birth weight. RV dilatation occurred in 49% and was significantlyassociated with moderate and severe pulmonary regurgitation (PR).Conclusion:Women with repaired TOF tolerate pregnancy relatively well, with no maternal mortality, and lowcomplication rate. Pulmonary regurgitation predicts RV dilatation. Fetal and neonatal outcomes were alsofavorable and women should be counselled as low to moderate risk. However, nearly half of women underwentCaesarean section, while probably more women should have a vaginal delivery.