AdvAnces in HemAtology

BB Recurrent miscarriage is a common disorder that affects 1–3% of women of reproductive age; the prevalence can be up to 5% for women with 2 pregnancy losses. In a majority of these women, however, especially in those with early pregnancy losses, the causative factors for pregnancy loss can include chromosomal aberration of the fetus; anatomic abnormalities of the uterus; endocrine disorders, such as hypothyroidism; infections; and hypercoagulable states, such as antiphospholipid syndrome and hereditary thrombophilia. The association between antiphospholipid syndrome and pregnancy complications in general, and in recurrent miscarriage in particular, is known. This syndrome is defined by the presence of antiphospholipid, anti-lupus coagulant, anti-cardiolipin, and/or anti-beta-2-glycoprotein I antibodies, and by the presence of either pregnancy complications or thrombotic events in the venous or arterial system. For inherited thrombophilia, the association is relatively new because the more common thrombophilic disorders such as factor V Leiden mutation or prothrombin mutation were reported approximately 15 years ago. Epidemiologic studies have largely demonstrated the association between hereditary thrombophilia and pregnancy complications, especially recurrent pregnancy loss after 10 weeks of gestation. However, it must be noted that not all studies demonstrated these associations; several other factors, such as ethnicity or geography, also affected results. For example, factor V Leiden and prothrombin mutation are more commonly found in the white population, but even in this population, there are differences. In the middle east, factor V Leiden is very common (approximately 10–15%), whereas in western Europe, the prevalence could be as low as approximately 2%. As expected, in areas where inherited thrombophilia (factor V Leiden or prothrombin mutation) is more prevalent, there were more reported cases in which it was associated with pregnancy complications. In areas where thrombophilia is less common, its association with pregnancy complications was reported less often, which could also mean that the study was too small (ie, prevalence is low) to demonstrate or refute an association. It could also indicate that other mechanisms could be involved. However, it is generally understood that there is an association—not a strong one—but a valid one. Additionally, the association is stronger when the patient experiences miscarriages that are recurrent, frequent, and in the later stages of pregnancy.