Long-term contraceptive effects of intrauterine neem treatment (IUNT) in bonnet monkeys: an alternate to intrauterine contraceptive devices (IUCD).

Antifertility effects of intrauterine neem treatment (IUNT) was studied in bonnet monkeys. A single administration of 1 ml of neem oil by an intrauterine insemination catheter blocked fertility for 7 to 12 months. The effect was, however, reversible as all the animals became pregnant subsequently and delivered normal babies. The neem oil treatment had no adverse effect on menstrual cyclicity and ovarian functions. The uterus of neem-treated animals showed normal morphology. Immunohistological studies, however, demonstrated a significant increase in the number of MHC-II antigen-positive cells in the uterine endometrium following neem treatment, indicating enhanced antigen-presenting ability of the uterus; a feature that may be related to the observed antifertility effect of neem oil. The present investigation demonstrates that an IUNT can be used for long-term, reversible contraception, without any apparent side effects, and that the method could provide an alternate to currently used intrauterine contraceptive devices (IUCD).