Antifertility by discontinuous treatment with buserelin in women

Paradoxical antifertility effects of LHRH agonists in various species have been described (Corbin and Bex, 1981). In women the continuous application of the LHRH agonist, buserelin, leads to inhibition of ovulation (Bergquist et al., 1979; Hardt et al., 1981). Progesterone secretion is dose-relatedly suppressed; estradiol production, however, shows a marked intra- and interindividual variance, even at contraceptive doses of buserelin. In the majority of women treated with such doses, this leads to irregular bleeding, in some cases going as far as amenorrhea. This results, on the one hand, in phases of endometrial stimulation of longer duration and, on the other hand, in phases of inadequate estradiol secretion accompanied by endometrial inactivity and estrogen deficiency symptoms. Because of these disadvantages a continuous long term treatment with LHRH analogs cannot be recommended for contraceptive purposes (Schmidt-Gollwitzer et al., 1983).