One of the most important issues for the women who have cardiac disease at their reproductive ages is pregnancy and the effects of the new physiological conditions that occur due to pregnancy. Pregnancies of the women who have applied prosthetic valve implantation at reproductive ages need to be watched very closely for the lives of the mother and the fetus. Furthermore, an urgent intra-cardiac operation for the pregnant patient must be required to protect the mother’s life as well as the fetus’ and thus have to be taken necessary precautions. A patient who had undergone mitral valve replacement in our clinic 3 years ago, urgently operated due to prosthetic valve thrombosis at the 27.th weeks of the pregnancy, and another patient who was in the 33rd weeks of pregnancy, had undergone valve replacement in emergency conditions because of pulmonary edema and heart failure from calcified severe mitral stenosis, have been evaluated in the accompaniment of the literature findings about the effects of the open heart surgery during the pregnancy over the mother and the fetus

Keywords : Pregnancy, open heart surgery, mitral valve, valve trombosis