Effect of pelvic endometrial implants on overall reproductive functions offemale rats

The effects of pelvic endometrial implants on the overall reproductive pote ntial of female rats were investigated. After homologous transplantation in the peritoneum, the ectopic endometrium developed into highly vascularized nodes that gradually increased in mass-until the 9th week postsurgery and then plateaued. In the presence of these implants, overall reproductive fun ction was adversely affected. The effect was of greatest magnitude during 5 0-70 days posttransplantation. As compared with values in corresponding con trols, ovulation was reduced by 43% (6 of 14) (p < 0.05), mating rate was r educed by 44% (12 of 27) (p < 0.025), and premature termination of pregnanc y occurred in 34% (5 of 15) of rats. Wastage of pregnancy, which included c omplete termination or reduction of fetal number, occurred during the posti mplantation course of gestation. Furthermore, 100% of the rats with transpl ants failed to respond to the copulomimetic stimulation for the induction o f pseudopregnancy (p < 0.01, compared with corresponding controls). However , on exposure to vasectomized males, 46% (6 of 13) of these rats exhibited development of pseudopregnancy (p < 0.05, compared with corresponding group receiving copulomimetic stimulation). Increased rate of mating failure and differential pseudopregnancy rates after copulomimetic and natural cervica l stimulation suggest that the rats with endometrial explants possibly had an absence or a short appearance of behavioral estrus. Hormonal assessment during the preovulatory phase showed a tendency toward lower mean levels of preovulatory estradiol and significantly lower LH (p < 0.01) and progester one (p < 0.01) concentrations. The adversely affected reproductive function s may be a secondary consequence of these altered endocrine milieus.