Clomiphene citrate-induced perturbations during meiotic maturation and cytogenetic abnormalities in mouse oocytes in vivo and in vitro

Objective: To determine if clomiphene citrate induces temporal perturbations during meiotic maturation and aneuploidy in mouse oocytes.

Design: A controlled dose study involving mouse oocytes in vivo and in vitro.

Setting: Clinical and academic research setting in a university medical center.

Intervention(s): Oocytes were obtained after superovulation and from mature follicles.

Main outcome measure(s): Cytogenetic analysis of oocytes for aneuploidy, premature centromere separation, premature anaphase, and single chromatids, and the frequencies of metaphase I and diploid oocytes.

Result(s): Clomiphene citrate resulted in a decrease in the number of ovulated oocytes and a significant (P<.05) increase in hyperploidy at 100 mg/kg in vivo. In vitro, 5.0 microg/mL of clomiphene citrate significantly (P<.05) increased hyperploidy and reduced the proportion of metaphase I oocytes.

Conclusion(s): These findings suggest that clomiphene citrate has the potential for inducing aneuploidy in mouse oocytes both in vivo and in vitro and that the rate of oocyte maturation is altered after clomiphene exposure in vitro. Additional data are needed to support the results of this study.