The influence of hyperestrogenism during in vitro fertilization on the fibrinolytic mechanism.

OBJECTIVE

To evaluate levels of various fibrinolytic factor antigens in women during ovulation induction using controlled ovarian hyperstimulation.

METHODS

Plasma tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), and the plasminogen activator inhibitors (PAI-1 and PAI-2) were evaluated and compared with plasma 17 beta-estradiol levels, ranging from 20 pg/mL to > 5,000 pg/mL during the course of treatment. Sixteen patients undergoing IVF were compared prior to (Controls) and following treatment with leuprolide acetate down-regulation followed by menopausal gonadotropin-CG ovulation induction for 14 days.

RESULTS

A significant positive correlation was found between tPA and PAI-1 during treatment, while tPA and PAI-1 were negatively correlated with estradiol levels. Mean levels of tPA and PAI-1 significantly decreased as estradiol levels increased.

CONCLUSIONS

As the plasminogen activator decreased with increasing estradiol levels, this suggests a potential for thrombosis. However, the major plasminogen activator inhibitor (PAI-1) also decreased; thus, the net clinical effect in terms of increased potential for thrombosis should be minimal. Furthermore, the levels of both tPA and uPA were still within normal ranges. The overall data from this study suggest that ovarian hyperstimulation with fertility-enhancing drugs does not enhance the potential for thrombosis even though there are elevated 17 beta-estradiol levels.