Embryo development and pregnancies from in-vitro matured and fertilized human oocytes

There is an increasing interest in retrieving immature oocytes in the absence of or with limited gonadotrophin exposure, with the aim of maturing them in vitro for embryo transfer purposes. The aim of this report is to present our experience of fertilization, embryonic development and pregnancies from in-vitro maturation cycles. A total of 18 patients underwent 21 cycles in which an average of 8.1 immature oocytes was retrieved after limited exposure to human menopausal gonadotrophin (HMG) and no exposure to human chorionic gonadotrophin (HCG). In one cycle, no oocytes were recovered. The oocytes were cultured for 44 h and 121 oocytes which reached MII were injected with a single spermatozoon. A total of 71 oocytes showed two pronuclei and 53 zygotes cleaved. Forty-four embryos were transferred in 17 cycles. Five weeks after embryo transfer, ultrasound examination indicated the presence of one gestational sac and one fetal heart beat in two patients. The results suggest that in-vitro matured oocytes can undergo fertilization and the resulting embryos may result in pregnancies. However, the success rate was not sufficient to recommend widespread use of the technique without further research.