Mode of long-term antifertility effect of intrauterine neem treatment (IUNT).

The mode of antifertility action of intrauterine neem treatment (IUNT) was studied. The effect of IUNT on ovarian functions and uterine responsiveness to ovarian hormones was examined in adult Wistar rats. The treated animals had normal reproductive cycles as indicated by the vaginal smears; serum progesterone levels were also in the normal range. Effect of exogenous estradiol following IUNT in ovariectomized rats showed comparable uterine weight gain as in control group; decidual cell reaction of the uterine epithelium following IUNT was also similar to that of control, indicating normal uterine responsiveness to ovarian hormones. Unilateral IUNT followed by mating resulted in degeneration of embryos on the treated side as noted between days 3-5 post coitum; normal embryos were seen on the contralateral side given peanut oil. The study shows that the mode of antifertility action of IUNT is not because of uterine unresponsiveness to the ovarian hormones but is due to impairment of embryo development. The results of this study thus confirm our earlier observations and show further that the antifertility effect of IUNT is at the pre-implantation stage, localized and without any adverse or toxic effect on the fetal development in the contralateral uterine horn of the unilaterally treated rats. The exact mechanism(s) of antifertility action of IUNT is being investigated.