The clinical and hormonal effectiveness of continuous infusion of
GnRH-agonist (A) for the treatment of
endometriosis was investigated. Five women with
endometriosis (stage II-IV) were treated with continuous
subcutaneous infusion of 200 micrograms of
GnRH-A (
Buserelin) per day for 24 weeks. Serum LH and FSH levels increased initially and then FSH levels declined markedly below pretreatment values within a week, followed by a gradual decrease to the normal range of LH levels within 4 weeks. Serum
estradiol decreased below early follicular phase levels within 1 to 3 weeks and thereafter continued to decrease to near castrate levels. The LH and FSH responses to 100 micrograms
GnRH challenge test were almost completely abolished within 2 weeks. The pulsatile secretion of LH and FSH were also abolished, when assessed at 16 weeks. The tendency toward the slight but significant elevation in FSH levels without an increase in
estradiol was noted from about 12 weeks. No
vaginal bleeding or
spotting was observed in four of the five patients during the course of the treatment. After completion of the 24 weeks of treatment, FSH increased rapidly to the early follicular phase range, and ovulation returned within 4 weeks. Two of the five patients became pregnant during cycles 2 and 5. From these results, we conclude that continuous sc infusion of
GnRH-A is highly effective for complete suppression of the pituitary-ovarian function in patients with
endometriosis. Further, this treatment appears to be safe and acceptable, because of its rapid reversibility and its lack of side effects.