Human Reproduction vol.12 no.5 pp.1094–1097, 1997

First-trimester repeated abortion is not associated with activated protein C resistance Juan Balasch1,3, Juan C.Reverter2, may be due to interference with the protein C dependent inactivation of factor Va by antiphospholipid antibodiesFrancisco Fábregues1, Dolors Tàssies2, Montserrat Rafel2, Montserrat Creus1 and (Mackworth-Young, 1990). The protein C system provides anticoagulant properties integral to control of the blood coagu-Juan A.Vanrell1 lation cascade. When activated, protein C is a physiological1Department of Obstetrics and Gynaecology and 2Haemotherapy anticoagulant, critical in limiting thrombosis by proteolyticand Haemostasis Unit, Faculty of Medicine-University of inactivation of factors Va and VIIIa (Mackworth-Young, 1990;Barcelona, Hospital Clı́nic i Provincial, C/Casanova 143, 08036-Barcelona, Spain Dahlbäck, 1995). A previously unrecognized mechanism for thrombophilia3To whom correspondence should be addressed concerning the protein C system has recently been described The present study was undertaken to investigate the poss- (Dahlbäck, 1995). It is characterized by an inherited resistance ible association between activated protein C resistance to the anticoagulant activity of activated protein C. In at least and first-trimester repeated abortion. Fifty-five consecutive 90 % of the cases, activated protein C resistance is caused b