Objective: Aim of our study was to analyze the influence of insulin receptor sensitization on the course of controlled ovarian stimulation in the program of assisted reproduction and to identify the availability of ovarian response improvement due to the reduced production of intraovarian androgens. Further we tried to identify the preventive influence of metformin on development of ovarian hyperstimulation syndrome.
Design: Prospective randomized controlled study of 172 patients involved in the assisted reproduction program from May 2000 to December 2001.
Setting: Centre of Assisted Reproduction, Department of Gynecology and Obstetrics, Medical Faculty, Masaryk University and University Hospital, Brno.
Material and methods: Patients undergoing the ovarian stimulation with increased risk of development of ovarian hyperstimulation syndrome due to the polycystic ovarian syndrome were included in the study and randomized to two groups. (1) Women in the first group used the insulin receptor sensitizing drug metformin together with gonadotropins, and (2) women in the second group underwent the classic stimulation protocol alone. The control group (3) consisted of patients with intact ovarian function and different infertility factor. Complex hormonal status was assessed before the treatment initiation and the level of androgens in the follicular fluid was investigated in all patients.
Results: Metformin during gonadotropin stimulation has significantly reduced the risk of ovarian hyperstimulation syndrome in women with PCOS. Significantly lower intraovarian androgen levels were documented in comparison to women without metformin and also when compared to patients with intact ovarian function. Metformin had also significantly reduced estradiol blood levels at the day of hCG application without significant influence on the number of obtained oocytes.
Conclusions: The risk of ovarian hyperstimulation syndrome development was significantly decreased in patients with PCOS in consequence to insulin receptors sensitization.