Effect of the exposure of intrafollicular oocytes to clomiphene citrate on pregnancy outcome in the rabbit.

This study was designed to determine if exposure of rabbit intrafollicular oocytes to clomiphene citrate (CC) affects pregnancy outcome after in vitro ovulation, in vitro fertilization (IVF), and embryo transfer (ET). Ovaries were perfused in the presence or absence of CC (10(-5) M) and estradiol (E2, 100 ng/ml). Human chorionic gonadotropin (hCG, 50 IU) was added to the perfusate of all ovaries. In vitro ovulated ova were retrieved, inseminated, and transferred to host rabbits. Neither CC nor CC + E2 significantly affected hCG-induced ovulation or fertilization. CC significantly reduced (P less than 0.025) percentage of ovulated ova resulting in offspring. Addition of E2 significantly (P less than 0.05) reversed the reduction in offspring associated with CC alone. These results may be due to the antiestrogenic effects of CC on the intrafollicular oocyte, which compromises postfertilization development.