The value of pre-treatment with gonadotrophin releasing hormone (GnRH) analogue in IVF-ET therapy of severe endometriosis.

Controversy concerning the optimal treatment of endometriosis and its related infertility still exists. Thirty-one women with moderate and severe endometriosis, who failed to conceive during previous in-vitro fertilization and embryo transfer (IVF-ET) cycles (protocol A), were re-admitted for the procedure following a period of hormonal suppression with a gonadotrophin releasing-hormone (GnRH) agonist (protocol B). Following GnRH analogue treatment, a significantly higher number of oocytes were recovered (P less than 0.0006); consequently more embryos were transferred and significantly higher clinical pregnancy rates per cycle (P less than 0.0001) were achieved. This difference may be directly related to the beneficial effect of the GnRH analogue on pelvic endometriosis, converting severe cases into mild ones with improved ovarian accessibility and probably oocyte quality.