Causes - Clotting - Symptoms

Several clotting disorders may cause problems during pregnancy or when you are trying to get pregnant. Examples of clotting disorders affecting pregnancy include:

Factor V Leiden
A clotting disorder that can cause blood clots to form in the blood vessels in the placenta during pregnancy. When this happens, pregnancy loss (miscarriage) can occur.

Antiphospholipid syndrome (APS) 
Another clotting disorder that affects up to 5 percent of women during pregnancy is APS. In this autoimmune disorder, a woman's body starts to produce antibodies that can cause blood clots. Most women avoid complications with APS, but some women do have problems, including deep vein clots, recurrent miscarriage, preterm labor, preeclampsia, restricted fetal growth, and other issues.

When a blood clot develops, it is called thrombosis. When a person has a tendency to form excessive blood clots over a length of time, he or she may have a clotting disorder called thrombophilia. Unfortunately, you may have thrombophilia and not know it, as you may not have any symptoms until a serious problem occurs.

Thrombophilia during pregnancy can result in serious consequences for you during pregnancy, including:

  • Placental abruption (a pregnancy complication in which the placenta partially or fully peels away from the uterus)
  • Pregnancy loss late in pregnancy, during the 2nd or 3rd trimester
  • Recurrent miscarriage

Also, estrogen, which is found in some oral contraceptives, may increase the risk of blood clots. Talk to your doctor before taking estrogen if you have a personal history or family history of clotting disorders.