Serial detection of plasma-factor XIII levels during the ovulatory cycle and estroprogestative contraception.

The authors examine the variations of plasma factor 13 (PF13) levels during the physiological cycle and estroprogestative contraception. Blood samples were taken from 8 women aged 21-26 who had used a combined estroprogestative oral contraceptive (OC), ethinyl estradiol 0.003 mg, levonorgestrel 0.15 mg, and from 10 healthy women aged 23-29, normally ovulating. Each subject underwent 4 venopunctures during the same month. The detection of PF13 levels from the 10 normally ovulating women resulting in the following mean values were found: 1) proliferative phase, day 6-10, 92%; 2) periovulatory phase, day 13-15, 67.2%; 3) secretive phase, days 20-23, 85%; and 4) premenstrual phase, day 27-29, 89.4%. There was a highly significant decrease of PF13 during periovulatory phase when compared with the other phases (p0.001). The detection of PF13 levels for the 8 women using OCs was: 1) end of 1st week from bleeding, day 7-8, 112.5%; 2) end of 2nd week, days 13-15, 113.1%; 3) end of 3rd week, days 20-22, 113.1%; and 4) end of 4th week, days 27-29, 113.1%; for the latter group no significant differences were found. The mean values resulted higher for the women using OCs in every serial sample. These results suggest a possible action of steroid hormones on PF13 levels and through it on the last step of coagulation process, the fibrinostabilization.