Activated protein C resistance can be associated with recurrent fetal loss.

As thrombosis of placental vessels may result in recurrent fetal loss, we analysed 39 consecutive women with recurrent fetal loss of unknown cause for activated protein C resistance. Factor V Leiden (FVL) mutation (19 cases) or APC resistance without FVL (nine cases) were found among these 39 women. Evaluation of 128 pregnancies in 19 patients with factor V Leiden mutation and 56 gestations in nine women with acquired APC resistance, revealed over 50% first-trimester abortions and 17% late abortions. Intra-uterine fetal death occurred in nine out of 19 FVL patients (47%). Only 34 of 184 gestations (18%) in hereditary or acquired APC-resistance women resulted in a live birth, with 11 of the 34 (32%) being premature deliveries. These data suggest that, in some patients with recurrent fetal loss, hereditary and acquired APC resistance are potential causes of vascular placental insufficiency.