Anovulatory effect of a LHRH antagonist in women.

The antagonistic analog of LHRH, NAc-D-p-Cl-Phe(1),(2), D-Trp(3),D-Phe(6), D-Ala(10)-LHRH was administered intramuscularly in a dose of 2 mg to ten normally ovulating women on day 12 of the menstrual cycle. Ovulation was inhibited in six patients, and two more presented an insufficient corpus luteum. No pregnancies were recorded in this series. In those patients who did not ovulate, it was demonstrated that the LHRH analog abolished the midcycle surge of both LH and FSH. Luteolysis evidenced by the rapid decline in progesterone levels was present in 2 cases. Bleeding pattern showed a tendency to delayed menses. The morphological findings in endometrial biopsies of 6 women exhibited mild proliferation. Further research along these lines is necessary for appraisal of this approach to birth control.