The improved pediatric-cardiological diagnostics and cardio-surgical therapy result in a numerical increase of women reaching reproductive age. Pregnancy considerably strains heart and circulation, which is countered by various cardiorespiratory mechanisms. Today mothers are not endangered vitally (exception: Eisenmenger-syndrome), but congestive heart failure, thromboembolic complications and rhythm disturbances may occur. Spontaneous abortion rate is 20-25%, prematurity and underweight are obligatory in cyanotic mothers. On the basis of an extensive review of literature the specific risks during pregnancy are discussed taking into account the hemodynamic situations in different heart defects. Anticoagulation of valve prosthesis depends upon the model and location of the prosthesis. Contraceptive counselling is deficient; it has to consider the risk of thromboembolic complications. Regarding the genetic risk we have to differentiate between each single defect and between the sex of the parents.