High doses of oral contraceptives do not alter endometrial alpha 1 and alpha v beta 3 integrins in the late implantation window.

OBJECTIVE

To assess the effects of an emergency contraceptive agent on the distribution of integrin heterodimers during that part of the implantation window.

DESIGN

Prospective, case-controlled study in a university-based Population Program. In the first ovulatory control cycle after the detection of LH surge, patients had endometrial sampling 11 days after the surge. In the next cycle the procedure was repeated 2 days after the administration of a postcoital contraceptive agent on day 9 after LH surge (100 g ethinyl E2 and 2 mg norgestrel).

MAIN OUTCOME MEASURES

The effects of postcoital contraceptives on the expression of integrin heterodimers (alpha 1 and alpha v beta 3 subunits) reported to be unique to secretory phase was determined.

RESULTS

All six specimens were consistent histologically with days 24 and 25 of the menstrual cycle by light microscopy. Using immunohistochemistry, strong membrane staining of endometrial glandular cells and superficial epithelium for both alpha 1 subunit and vitronectin (alpha v beta 3) receptor was observed in treatment and controls. No diminution of intensity or distribution was observed relative to pretreatment controls.

CONCLUSIONS

There is no apparent change in the level of these two integrins in the human endometrium when high-dose oral contraceptives are given in the later stages of the implantation window. This suggests that the high doses of steroids used in emergency contraceptives may exert their effect through more complex mechanisms than endometrial cell surface changes.