Maturation of human oocytes in vitro

Background: Immature oocyte retrieval followed by in vitro maturation is a promising infertility treatment option. In patients with morphologically normal ovaries and regular menstrual cycles and in patients with polycystic ovary syndrome (PCOS) we attempted to assess the success of oocyte in vitro maturation in in vitro fertilization (IVF) procedures.Methods: Retrospectively we analyzed 87 IVF procedures with in vitro maturation of oocytes carried out in 73 infertile couples treated at the Maribor Teaching Hospital. We compared the success following three different hormone priming protocols: regular cycling patients with normal ovaries and without hormone priming (Group A, n = 27); patients with PCOS and hormone priming with follitropin (follicle stimulating hormone, FSH) (Group B, n = 22); patients with PCOS and hormone priming with human chorionic gonadotrophin (hCG) (Group C, n = 38). Success of the procedure was evaluated on the basis of the ability of oocytes to mature, fertilize and develop into embryos, and on the basis of the quality of embryos and their ability to implant in the uterus.Results: In regular cycling patients with normal ovaries (n = 27) we obtained a significantly lower number of immature oocytes (3.2 ± 2.5) compared with patients with PCOS and FSH priming (11.7 ± 7.2) or those with PCOS and hCG priming (10.4 ± 7.2). The oocyte maturation rate, the fertilization rate and the embryo cleavage rate were as follows: in Group A 57.7 %, 63.2 % and 91.7 %, in Group B 57.6 %, 66.2 % and 90.0 %, and in Group C 58.0 %, 66.2 % and 91.0 % (the differences between groups were not statistically significant). Six pregnancies were recorded only in patients with PCOS. The pregnancy rate per embryo transfer was 1/20 (5.0 %) in patients with FSH priming, and 5/33 (15.2 %) in patients with hCG priming.Conclusions: Oocyte in vitro maturation is successful in patients with normal ovaries and regular menstrual cycle as well as in those with polycystic ovary syndrome. Clinically the method of in vitro maturation of oocytes in IVF procedures is particularly justified in patients with PCOS. The hCG priming protocol proved the most successful hormone priming protocol for patients prior to puncture of immature follicles.