Hereditary thrombophilia and adverse pregnancy outcomes

Background: Multiple studies have found a relatively increased risk of placenta-mediated pregnancy complications in women with congenital thrombophilia, especially early recurrent pregnancy loss, fetal loss, early-onset preeclampsia, intrauterine growth restriction, and premature abruption of normally positioned placenta. However, the extent of the association and the absolute risk are very modest, but they significantly increase in pregnant women with severe obstetric complications. Conclusions: There is convincing evidence that deficiency of natural anticoagulants (antithrombin, protein C, protein S) is a risk factor for late fetal loss. Factor V Leiden G1691A gene mutation and prothrombin G20210A gene mutation are associated with a double risk for early and unexplained recurrent pregnancy loss and for non-recurrent late fetal loss. The association of congenital thrombophilia with preeclampsia is much more uncertain, being probably limited factor V Leiden G1691A gene mutation and more severe cases of preeclampsia. Fewer data are available on intrauterine growth restriction (IUGR) and premature abruption of the normally positioned placenta. There is insufficient evidence to suggest an association of other forms of congenital thrombophilia with adverse pregnancy outcomes. In addition, genetic and epidemiological research suggests that placenta-mediated pregnancy complications are of polygenic multifactorial etiology, with a risk determined by the interaction of multiple genetic variants and other risk factors.