ORIGINAL ARTICLE Activated protein C resistance – in the absence

Summary. Background: Activated protein C (APC) resistance with or without factor VLeiden (FVL) is amajor risk factor for venous thromboembolism. Many previous pregnancy studies have been focused onAPC resistance caused by FVL. Very few have investigated APC resistance in the absence of FVL (APCRFVL–).Material and methods: In a prospective study of 2480 unselected gravidae, blood was drawn in early pregnancy (mean 12 weeks of gestation). APC resistance was analyzed by an APTT-based method (CoatestAPC-resistance) and the presence of FVL was determined by PCR. The APCRFVL– group had similar mean APC resistance ratio as the hetero-zygous carriers of FVL.The analyseswere carried out no earlier than 3 months after delivery when all data were recorded. Small-for-gestational age (SGA) was used as a proxy for intrauterine growth restriction. Results: When compared with the control group, women with APCRFVL – had no increased risk of SGA, pre-eclampsia, first trimester fetal loss or venous thromboembolism. However, they had an increased risk of second trimester fetal loss (7.3 % vs. 2.7%, P 0.01), and a tendency of being overweight (17.3%vs. 12.6%,P 0.19) and of delivering extremely preterm (2.8 % vs. 1.0%, P 0.11). Conclusion: Women with APC resistance not caused by FVL werenot at increased risk for SGA,pre-eclampsia, first trimester fetal loss, or abnormal blood loss. However, they showed an increased prevalence of second trimester fetal loss