What is thrombophilia and how is it related to female fertility?
Τhrombophilia is a disorder involving the genetic predisposition to form a blood clot (deep venous or arterial thrombosis) potentially leading to stroke, heart attack, or pulmonary embolus. Thrombophilia may also lead to clotting of the arterial or venous blood supply to an organ such as the kidney or in cases involving pregnancy, the placenta.
The growth of a successful pregnancy depends on an adequate blood supply from the mother through her baby’s placenta. Therefore if the blood vessels on the maternal side of the placenta become clotted termed thrombosed, then the baby is unlikely to get an adequate blood supply leading to being small for gestational age, growth restricted, or in severe cases could cause fetal death.
Thrombophilia and infertility
Thrombophilia is not a cause of infertility and women with thrombophilic defects can have normal pregnancies. Thrombophilia, however, is considered a significant risk factor for recurrent pregnancy loss, especially after the first trimester. The timing of fetal demise among women with pregnancy loss provides diagnostic clues since thrombophilias are not likely to be involved in miscarriages before 10 weeks of gestation and are most commonly associated with pregnancy complications later during the second trimester and early third trimester of pregnancy.
The inherited thrombophilias most often associated with recurrent pregnancy loss include hyperhomocysteinemia, activated protein C resistance associated with mutations in factor V, deficiencies in proteins C and S, mutations in the prothrombin gene promoter, mutations in prothrombin, and mutations in antithrombin III. These inherited disorders are mainly autosomal dominant and display a wide variation of how they may manifest a particular disorder in the person carrying these genes. These genes are also widely present in the general healthy population, between 2% to 15% depending on the study; so the mere presence of one of these mutations in women with recurrent pregnancy loss does not necessarily mean that it is the reason for their losses. Thrombotic events not surprisingly are more common in individuals having combinations of two or more of these inherited genes. Up to 50% of women who have a pulmonary embolus during pregnancy due to deep venous thrombosis have genetically acquired thrombophilia as represented by having one or more of these thrombophilic mutations.
Thrombophilia and pregnancy
Thrombophilia can cause complications in pregnancy: These complications can be: placental abruption, prematurity, miscarriage, birth of low birth weight newborns, and delayed intrauterine fetal development.
Pregnancy due to increased estrogen and pressure from the swollen uterus to the vessels of the abdomen can cause excessive blood clotting and therefore there is a risk of thrombosis and blockage of blood vessels of the placenta or endometrium which increases the risk of miscarriage and miscarriage.
Only one type of genetic thrombophilia, one caused by a mutation in factor V Leiden, has been linked to problems in both the fetus and the newborn.
Thrombophilia is not prohibitive for pregnancy, a thrombophilia test should be performed and if diagnosed, the hematologist who will monitor the pregnant woman in conjunction with the gynecologist should give her the appropriate anticoagulant treatment.
When is testing for Thrombophilia indicated?
Thrombophilia testing is not performed in all women, but is mainly recommended for the following categories:
- Women with a previous normal pregnancy and miscarriage in the second.
- Women over 35 with two miscarriages or two failed IVF attempts.
- Women under 35 with three miscarriages or three failed IVF attempts.
- Couples who are infertile for three years.
- Women who have immune problems with autoimmune diseases such as rheumatoid arthritis or lupus.
Is thrombophilia hereditary?
Thrombophilia can be inherited or acquired. If it is inherited it is usually due to a defective gene inherited from the parents. The main genes that cause thrombophilia are factor V Leiden and the G20210A variant of prothrombin.
Acquired is the result of a malfunction of the immune system, which causes the production of an antibody that interferes with the mechanism of blood clotting and can result from various conditions, such as diabetes, cancer, obesity, pregnancy, immobility, childbirth. There is also the Acquired lupus gene and cardiolipin B2 glycoprotein antibodies. These antibodies are known as antiphospholipid syndrome.
How is Thrombophilia Diagnosed?
- Blood tests are needed to diagnose thrombophilia.
- Exactly what these will be are determined by the doctor according to the woman’s personal history, her hereditary history, and aggravating factors such as smoking, obesity, and other diseases.
- Basic tests are factor V Leiden, homocysteine, prothrombin, autoimmune test, general blood count, clotting times, Protein C, S test, cardiolipin test, lupus test, MTHFR.
Thrombophilia and treatment
If a woman develops thrombophilia, the reproductive gynecologist is called upon to evaluate the test results and take them into account with the medical history and clinical picture of the woman and the couple as a whole. Thrombophilia is treated by improving blood circulation with appropriate anticoagulant therapy (low molecular weight aspirin or heparin).