I am not an expert in cardiovascular surgery. Both mechanical and porcine valves can be used in pregnancy. The mechanical valve is more durable whereas the porcine valve might need replacement in about 10 years. Mechanical valve requires continuous anticoagulation. It means you will be taking Coumadin pills and checking you blood every few weeks until rest of your life. Since Coumadin is contraindicated in pregnancy, be ready to switch to Heparin or Lovenox or Fragmin injections while you are pregnant.
The risks of fetal loss, hemorrhage, prolonged hospitalization, and possibly teratogenesis associated with mechanical valve replacement and anticoagulation during pregnancy remain considerable. (From Duke University Medical Center.)
Therefore, the answer to your question is: Bioprostheses (porcine valve) remain the devices of choice for young women willing to trade earlier reoperation for the opportunity of pregnancy.
[This message has been edited by bird123 (edited 07-19-2002).]