Oral contraceptives (OCs) affect plasma levels of haemostatic factors and the use of OC is a risk factor for development of cardiovascular disease. This study addressed the effect of OCs on FSAP in human blood.

Women were analysed that took oral contraceptives with different estrogen and progestin dosage. Marburg I variant, FSAP antigen and FSAP activity was measured at the start and after 6 cycles of OC. Marburg I was found to be present in 49 (8.4%) of the women, in all three treatment groups (P=0.44). Marburg I was associated with significantly reduced levels of FSAP (P<0.001). OC use increased the median plasma concentration of FSAP antigen by 25% and FSAP activity by 58% (P<0.001). The relative increase in FSAP activity was significantly higher in women carrying the wild type genotype (63%) than in women carrying the Marburg I variant (50%) (P=0.01). The increase in FSAP was independent of the estrogen dosage and progestin (P>0.1).

In conclusion, OCs increased FSAP in plasma independent of the estrogen dosage and the progestin component but with less significance in women carrying Marburg I genotype than in women with the wild type genotype.

Authors and Source
JJ Sidelmann, SO Skouby, C Kluft, U Winkler, F Vitzthum, H Schwarz, J Jespersen
Poster presentation ISTH 2009: OC-MO-090  

Titel
The effect of monophasic oral contraceptive regimens on factor VII-activating protease – a randomized multicentre study