F2 and placental abruption: The G to A transition at the 20210 position in the prothrombin gene is associated with elevated prothrombin levels and is a risk factor for thrombosis.23 Studying 80 women with RSA and 100 fertile women, Foka et al.22 detected a higher frequency of preeclampsia, abruptio placentae, intrauterine growth restriction and stillbirth among those who were carriers of this mutation.