Preconceptional management strategies in women with thrombophilic disorders
The discussion of thrombophilic disorders in preconceptional management is important, as it is one of the leading causes of maternal morbidity and mortality, despite being a rare complication in pregnancy with a prevalence of only 0.06-0.1%.
Although many women have no prior history of venous thromboembolism (VTE), those with thrombophilic disorders must take special precautions in the preconception period, as the risk of VTE increases fivefold for this population.Pregnancy increases the risk of VTE through all avenues of Virchow's triad: including increased hypercoagulability through increased levels of fibrinogen, factors II, VII, VIII, X, and XII; venous stasis due to compressive forces from the gravid uterus; and endothelial injury in cases of caesarean section.
Thrombophilias can be categorized as inherited or acquired conditions. The most common inherited thrombophilias, with associated odds ratio (OR) for development of VTE during pregnancy, include factor V Leiden (OR 34.4) and prothrombin gene (G20210) mutation (OR 26.4), while the primary acquired thrombophilia is antiphospholipid antibody syndrome (OR 15.8) (74-77).
Women of child-bearing age with known thrombophilia, as well as those with a history of VTE, should undergo special surveillance and investigations in the preconception period to stratify the risk for VTE in pregnancy. Those with an unprovoked VTE event can be managed with surveillance alone, or surveillance in the antepartum period followed by thromboprophylaxis in the postpartum period, while those with hormonal-provoked VTE and known thrombophilia (inherited or acquired) should undergo thromboprophylaxis for VTE in pregnancy. Due to the difference in treatment, it is an important distinction to make in the preconception period, and accordingly, a prior history of VTE and thrombophilias should be screened for in the preconception period. Although screening should be completed in the preconception period, there is no indication for thromboprophylaxis in the preconception period, unless the condition itself requires this treatment. The recommended thromboprophylaxis in the antepartum period may include daily low-molecular-weight heparin administration, with the risks and benefits of treatment discussed on an individual basis with each woman.