Prediction of changes in levels of haemostatic variables during natural menstrual cycle and ovarian hyperstimulation.

To find if there is a relation between levels of haemostatic variables at low and high hormonal levels (oestradiol and progesterone) in an individual, blood samples were drawn from 12 women repeatedly during one menstrual cycle (Study I) and from 14 women undergoing in vitro fertilization, before hormonal stimulation and daily during the periovulatory period (Study II). Regression coefficients were calculated between minimum (independent) and maximum (dependent) values in both studies. In Study II highly significant regression coefficients were found between oestradiol minimum (pretreatment) and maximum (median 105 and 4730 pmol/l, respectively) for coagulation factors FVIII, von Willebrand Factor (antigen), FVII (activity and antigen), fibrinogen, protein C, protein S (free), antithrombin, plasminogen and plasminogen activator inhibitor-1; furthermore, between progesterone-minimum at day -3 or -2 (related to ovum pick up) and maximum (median 4.7 and 98 nmol/l, respectively) for FVIII, von Willebrand Factor, FVII (activity and antigen), protein C, protein S (free), and plasminogen. In Study I, where much lower hormonal levels were obtained at maximum (oestradiol median 297 pmol/l and and progesterone 47 nmol/l), the same pattern was observed especially for FVIII, FX, fibrinogen, plasminogen and plasmin inhibitor. Thus, the concentration of a haemostatic variable at a low oestradiol or progesterone level can predict the level at a high hormonal level.