['Pregnancy in women with biological heart valve prosthesis might lead to a faster degeneration of the prosthesis. We analyzed the rate of prosthesis replacement and the outcome of pregnancies in women with biological valve prosthesis.', 'Between 1976 and 2006, 100 female patients aged 18-40 years at time of the study, underwent a valve replacement with a bioprosthesis or a homograft. At a mean interval of 10.8±8 years, 87 patients were evaluated by a questionnaire.', 'A biological prosthesis was implanted in 45 patients (52%), while 42 patients (48%) received a homograft. After valve replacement, 33 patients (38%) had a total of 56 pregnancies with a live-birth rate of 77% (n=43). There were 9 (16%) miscarriages, 4 (7%) therapeutic abortions and no stillbirths. There was no maternal death, thromboembolic event or structural valve deterioration during pregnancy. Out of 87 patients, 31 (36%) required a valve re-replacement at a mean time of 9.5±5 years. Neither age, valve type, valve position nor pregnancy were a risk factor for a valve re-replacement. The freedom from valve re-replacement at 5 and 10 years, was 96±3% and 73±9%, respectively for patients after a pregnancy compared to 93±4% and 52±10%, respectively for patients without a pregnancy (p=0.2).'] Does pregnancy accelerate biological valve degeneration?