BACKGROUND: In the past 3 decades, the arterial switch procedure has replaced the atrial switch procedure as treatment of choice for transposition of the great arteries. Although survival is superior after the arterial switch procedure, data on preg- nancy outcomes are scarce and transposition of the great arteries after arterial switch is not yet included in the modified World Health Organization classification of maternal cardiovascular risk. METHODS AND RESULTS: The ROPAC (Registry of Pregnancy and Cardiac disease) is an international prospective regis- try of pregnant women with cardiac disease, part of the European Society of Cardiology EURObservational Research Programme. Pregnancy outcomes in all women after an arterial switch procedure for transposition of the great arteries are described. The primary end point was a major adverse cardiovascular event, defined as combined end point of ma- ternal death, supraventricular or ventricular arrhythmias requiring treatment, heart failure, aortic dissection, endocarditis, ischemic coronary events, and thromboembolic events. Altogether, 41 pregnant women (mean age, 26.7±3.9 years) were included, and there was no maternal mortality. A major adverse cardiovascular event occurred in 2 women (4.9%): heart failure in one (2.4%) and ventricular tachycardia in another (2.4%). One woman experienced fetal loss, whereas no neonatal mortality was observed. CONCLUSIONS: Women after an arterial switch procedure for transposition of the great arteries tolerate pregnancy well, with a favorable maternal and fetal outcome. During counseling, most women should be reassured that the risk of pregnancy is low. Classification as modified World Health Organization risk class II seems appropriate.