Blood-Clotting Disorders: How They Affect Your Ability to Get Pregnant

Normally, a small cut on a blood vessel wall causes the body to form a blood clot to seal it and stop the bleeding. However, some people form blood clots too easily. If you tend toward excessive blood clotting or if the clots don’t dissolve properly, you’re said to have a blood-clotting disorder.

Several things can alter the body’s normal blood clotting process. For example, smoking, plaque on the inside of the arteries (atherosclerosis), and birth control pills can increase the risk of excessive blood clots.

Pregnancy can also lead to excessive blood clotting. Since more clotting factors are in a woman’s blood during pregnancy, a pregnant woman is six times more likely to develop blood clots. Also, because the uterus compresses the veins during pregnancy, the blood flow slows down as it moves through the vessels and may lead to blood clots.

What Causes Blood Clotting Disorders?

A blood clotting disorder is a result of the body making either too many blood clotting factors or too few anti-clotting factors that limit clot formation.

Excessive blood clotting may be caused by genetic disorders which are inherited from one or both parents. Two common disorders are “factor V Leiden” and “prothrombin mutations.” They increase the risk of developing a potentially dangerous blood clot which could travel to other parts of the body. They may also cause small blood clots to develop within placenta tissue which could lead to a miscarriage.

Some blood clotting disorders are due to problems in the immune system. Lupus anticoagulants are antibodies that attack those substances that the body normally produces to prevent blood clotting. People with those antibodies have a high risk of blood clotting.

How Do Blood Clotting Disorders Affect Pregnancy?

Genetic and immune clotting disorders are associated with recurrent miscarriage. If you have factor V Leiden and prothrombin mutations, you may also be at risk of having a placental abruption, which happens when the placenta partially or completely separates from the uterine wall before delivery. This results in heavy bleeding which is dangerous for the pregnant woman and the baby.

Factor V Leiden and prothrombin mutations may also increase your risk of other complications during pregnancy, such as pregnancy-induced high blood pressure and slow fetal growth.

Although most women with these mutations have normal pregnancies, it’s important to talk to your doctor about your own risk of abnormal blood clots and pregnancy complications.