Gossypol in female fertility control: ovum implantation and early pregnancy inhibited in rats.

Intramuscular administration of gossypol to normally cycling female rats induced an irregularity of the cyclic pattern for as long as the treatment was continued. Furthermore, administration of gossypol from days 0 (day of sperm-positive vaginal smear) to 8 of pregnancy prevented the normal maintenance of pregnancy. Serum values of progesterone and estradiol 17 beta in gossypol-treated normally cycling and pregnant rats were significantly lower than the control levels. The supplement of a combination of exogenous progesterone and estradiol 17 beta eliminated the inhibitory effects of gossypol on ovum implantation and the maintenance of pregnancy. Our results indicate that gossypol may have some usefulness in female fertility control.