ROLE OF HYPOESTROGENISM OR SEX STEROID ANTAGONISM IN ADHESION FORMATION AFTER MYOMETRIAL SURGERY IN PRIMATES

Objective: To determine the contribution of estrogen in the developmen t of pelvic adhesions during myometrial surgery. Design: A randomized, prospective study in the nonhuman primate. Setting: A primate colony, Department of Obstetrics and Gynecology, Eastern Virginia Medical Sch ool. Interventions: All primates were assigned prospectively to one of three treatment groups: [1] GnRH analogue (GnRH-a), [2] mifepristone, or [3] vehicle control. After 3 months of treatment, a standard uteri ne fundal hysterotomy, for full thickness endometrial biopsy, was perf ormed at the time of exploratory laparotomy, with subsequent scoring o f utero-omental adhesions to the hysterotomy site at a future staging procedure based upon adhesion area, vascularity, and tenacity. Serum w as drawn on the day of surgery for E(2) determination. Endometrial hei ght, from the surface interface between the endometrium and myometrium , was used as a bioassay of estrogen activity. Results: The hypoestrog enic (GnRH-a) group and the mifepristone group had significantly fewer utero-omental adhesions compared with the normally cycling control mo nkeys as measured by a lower adhesion score. Similarly, the endometria l thickness was significantly reduced in the GnRH-a and mifepristone g roups (one-third) compared with the cycling controls, demonstrating th e effects of either hypoestrogenism or noncompetitive estrogen antagon ism. Serum E(2) on the day of surgery was predictive of the postoperat ive adhesion score by both a regression analysis and analysis of covar iance. Conclusions: The actions of E(2) seem to have a dramatic effect on the formation of pelvic adhesions after myometrial surgery.