Rats were treated with indomethacin (prostaglandin synthesis inhibi tor) on Day 5 of pregnancy then killed 2 days later. As compared to control pregnant rats, indomethacin treatment (1 mg/100 g body weight given S/C at 05:00, 10:00 and 15:00 h) did not reduce the incidence of pregnancy among treated tats or the number of implantation swellings. However, indomethacin treatment significantly decreased (P/ 0.01) the weight of uterine horns and significantly reduced (P/ 0.001) the size of implantation swellings. Aggregation of the implantation swellings was observed near the ovarian end of the uteri of indomethacin treated rats. Besides, a significant increase(P/ 0.05) in the sites of early em bryonic death was observed in uteri of indomethacin treated rats.
These data may confirm the importance of prostaglandin synthesis during early pregnancy in rats.