Inherited risk of thrombosis of the fetus and intrauterine fetal death

Objective: To test the hypothesis that abnormal placentation resulting in intrauterine fetal death (IUFD) is associated with coagulation abnormalities in the fetus. Study design: We analyzed fetal DNA from umbilical cords from 139 pregnancies complicated by intrauterine fetal death during 1994-1998 (cases). Fetal DNA was tested for the presence of factor V Leiden and prothrombin G20210A mutations. The prevalence of these thrombophilic mutations among cases were compared with the prevalence in a historic control group. Results: Overall, a higher prevalence of fetal genetic risk factors was found in cases (9.8%) as compared to fetuses born from an uncomplicated pregnancy (2%, odds ratio 4.8, 95% CI 1.1-22). Second trimester intrauterine fetal death occurred more frequently in cases with the factor V Leiden mutation as compared with the control group (8/64 versus 0/92). For intrauterine fetal death and factor V Leiden a high risk was found concerning abruption placentae (odds ratio 7.6, 95% CI 1.5-37). Conclusion: The prevalence of fetal genetic risk factors associated with an increased risk for thrombosis was higher in pregnancies complicated by intrauterine fetal death suggesting an important role of abnormal coagulation in placentation.