A: A deep venous thrombosis is a blood clot that forms within deep veins in the body, usually within the legs or arms. These clots can cause pain, redness and swelling in the affected extremity. They have the potential to dislodge and run the risk of becoming life threatening if they travel to the lungs. This is called a pulmonary embolism.

Women who had a prior DVT are at increased risk of a recurrent DVT with pregnancy, when certain factors increase the clotting capacity of blood.

Anti-coagulant medication can prevent a recurrence of this condition. Currently, two anti-coagulants are safe to use in pregnancy: heparin and low-molecular weight heparin. Heparin use requires repeated blood tests. Low-molecular weight heparin can be safely used in pregnancy and doesn't require intensive monitoring. It can't cross the placenta and won't affect a growing baby. In contrast, the oral anti-coagulant Coumadin® transfers across the placenta and can't be used during pregnancy.

Anticoagulant medication will need to be continued throughout your pregnancy and for several weeks following delivery, while the risk of clotting remains high. At the time you enter labor you will temporarily discontinue the medication to minimize excessive blood loss during labor and allow you to safely choose an epidural anesthetic if you so desire.

Prior to becoming pregnant meet with your doctor to discuss strategies for a healthy pregnancy.