About Inherited Thrombophilias

Inherited thrombophilias are a group of disorders that raise your risk of having a blood clot during pregnancy and after delivery. Although all women who are pregnant have an increased risk of developing blood clots, this risk is increased further depending on other factors, specifically, a personal or family history of clots. Blood clots cause blockages of blood vessels that decrease the blood flow to internal organs including the placenta.

In addition to complications for the mother, inherited thrombophilias have been associated with fetal growth delay, stillbirth, early-onset severe preeclampsia, placental separation (abruption), and in some cases pregnancy loss after 10 weeks gestation.

Types of Thrombophilias

The most common inherited thrombophilias are:

  • Factor V Leiden mutation
  • Prothrombin G20210A mutation
  • Methylenetetrahydrofolate reductase C677 (MTHFR) mutation
  • Antithrombin III (AT III) deficiency
  • Protein C deficiency
  • Protein S deficiency

Although most of these conditions are inherited, you may not have a known family history of blood clots. Your pregnancy may be the first time these conditions appear in your family.

Treatment of Thrombophilia During Pregnancy

Since clots may form with inherited thrombophilias, some women are prescribed blood-thinners during pregnancy and for 6 weeks after delivery.

Low-molecular weight heparin and unfractionated heparin are blood thinners that are frequently given and are safe to take in pregnancy. Maternal-fetal medicine specialists will evaluate your specific thrombophilia, pregnancy history, and personal and family history. Your pregnancy will be carefully followed, and a plan for anticoagulation appropriate for your specific case will be made.

In some cases, an evaluation by a hematologist (specialist in blood and clotting disorders) may be needed, and this appointment can be arranged through your maternal-fetal medicine specialist.

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