In a series of 416 women with congenital heart disease seen in the Royal Brompton National Heart and Lung Hospital, London, and the Hospital Giovanni Bosco, Torino, Italy, there were 822 pregnancies. The outcomes of 96 pregnancies in 44 patients with cyanotic congenital heart disease were studied. Patients with the Eisenmenger reaction were excluded. Patients were divided arbitrarily into groups according to the type of maternal congenital cardiac anomaly, and factors influencing maternal and fetal outcome were evaluated. The incidence of maternal cardiovascular complications was high (32%), with one death from endocarditis 2 months after delivery. Forty-one (43%) of 96 pregnancies resulted in a live birth; 15 (37%) were premature. Mean weight of full-term infants was 2575 g.Univariate analysis suggested that maternal disease, Ability Index, hemoglobin, and arterial oxygen saturation before the pregnancy were factors that discriminated between successful and unsuccessful fetal outcome, with hemoglobin and arterial oxygen saturation being the most important predictors.Women with cyanotic congenital heart disease can go through pregnancy with a low risk to themselves, with frequent treatable complications, but there is a high incidence of miscarriage, premature births, and low birth weights. An incidence of congenital heart disease in the fetus of 4.9% (2 of 41 live births) is higher than that found in the normal population. (Circulation. 1994;89:2673-2676.)