Influence of the LH-RH analogue buserelin on cyclic ovarian function and on endometrium. A new approach to fertility control?

The long-acting stimulatory luteinizing hormone - releasing hormone analogue D-Ser(TBU)6-EA10-LH-RH (buserelin) was administered intranasally once daily in a dose of 400 mcg to 24 normally ovulating women and to 4 women with pre-existing endocrine dysregulation. Ovulation was inhibited in 136 out of 156 treatment months. In 20 treatment months, progesterone values temporarily increased indicating luteinization of follicles or ovulation with defective corpus luteum function. Estradiol secretion showed a tendency to lower values as treatment progressed but individually indicated follicle maturation until the end of the observed medication period. Bleeding pattern ranged from menses-like bleeding in regular as well as irregular intervals to amenorrhea. The morphological findings of 31 endometrial biopsies of 20 volunteers ranged from atrophy (n = 4) to proliferation (n = 25) with early signs of hyperplasia as well as early secretory transformation (n = 2). The morphological alterations indicate that unopposed estrogen stimulation of the endometrium is the main problem of long-term contraception with the dose schedule of buserelin used.