The effects of metformin on ovum implantation and pregnancy outcome in rats with induced PCOS

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. Metformin which is effectively used for the treatment of anovulatory PCOS improves pregnancy rate and endometrial receptivity and reduces the risk of miscarriage. The aim of this study was to evaluate the effects of metformin on the endometrium, the number of fetuses and hormonal levels of PCOS rats. Forty female adult Sprague-Dawley rats were assigned randomly into four equal groups. Group I: control rats, group II: rats receiving metformin (150 mg/kg/day), group III: Estradiol Valerate-induced PCOS rats (4 mg/rat) and group IV: induced PCOS rats receiving metformin. Body weight and serum levels of glucose, LH, FSH, testosterone, progesterone and estradiol were measured. Following mating, each group was divided into two subgroups and the rats were sacrificed on the 5th and 15th day of gestation to evaluate endometrial reaction to implantation and fetus count, respectively. Hormone assay showed a significant increase in testosterone, estradiol, LH, FSH and blood glucose levels in group III compared to the controls (P≤0.01) and a significant decrease in blood glucose in group IV versus group III (P≤0.01). Progesterone concentration had no significant differences between groups III and the controls. Weight was higher in group III than group I but it had no decrease after metformin administration. No significant differences were detected regarding implantation rate and number of fetuses in all rats. Metformin has significant effects on pregnancy rate and the hormonal and blood glucose levels of Estradiol Valerate-induced PCOS rats.