Background Pregnant women with congenital heart disease (CHD) are susceptible to cardiovascular, obstetric, and offspring complications. In women with CHD, cardiac dysfunction may compromise uteroplacental flow and contribute to the increased incidence of obstetric and offspring events. Methods and Results We performed a prospective multicenter cohort study of pregnant women with CHD and healthy pregnant women. We compared clinical, laboratory, echocardiographic, and uteroplacental Doppler flow (UDF) parameters at 20 and 32 weeks gestation, and pregnancy outcome. We related cardiovascular parameters to UDF parameters and pregnancy outcome in women with CHD. We included 209 women with CHD and 70 healthy women. Cardiovascular parameters (N-terminal pro-B-type natriuretic peptide, left and right ventricular function) differed between both groups. UDF parameters were impaired in CHD women (umbilical artery pulsatility and resistance index at 32 weeks in CHD versus healthy women, P=0.0085 and P=0.017). The following cardiovascular parameters prepregnancy and at 20 weeks gestation were associated with UDF (umbilical artery resistance index) at 32 weeks at multivariable analysis: (1) right ventricular function (tricuspid annular plane systolic excursion) (P=0.002), (2) high N-terminal pro-B-type natriuretic peptide (P=0.085), (3) systemic (P=0.001), and (4) pulmonary (P=0.045) atrioventricular valve regurgitation. Women with CHD had more obstetric (58.9% versus 32.9%, P Conclusions UDF parameters are abnormal in pregnant women with CHD. Cardiovascular function is associated with an abnormal pattern of UDF. Compromised UDF may be a key factor in the high incidence of offspring and obstetric complications in this population.