[In vitro maturation and fertilization of unstimulated immature oocyte for the treatment of infertile women]

Abstract

Objective: To evaluate the efficacy of in vitro maturation (IVM) and fertilization of unstimulated immature oocytes for the treatment of infertile women.

Methods: Fifty-four cycles of IVM were carried out in 40 patients including 26 women with infertility due to polycystic ovary syndrome (PCOS), and 14 patients with history of assisted reproductive technology (ART) failure. Transvaginal ultrasound-guided oocyte collection was performed during menstrual cycle days 9 - 12 without pretreatment of gonadotropins. After 24 - 48 hours of culture, the metaphase II stage oocytes were inseminated by intracytoplasmic sperm injection (ICSI). Embryo transfer was performed 2 or 3 days after ICSI. Laser assisted hatching was done before embryo transfer.

Results: Seven cycles were cancelled and the cancel rate was 13% (7/54). A total of 857 immature oocytes were obtained with the mean numbers of 18.2 per cycle, and 632 oocytes developed at MII stage (73.7%, 632/857). A total of 476 oocytes were fertilized by ICSI (75.3%, 476/632), with a cleavage rate of 91.2% (434/476). Embryo transfer was performed in 47 cycles and the mean number of embryos transferred were 4.3 per cycle (range: 2 - 6). The mean endometrial thickness on the day of embryo transfer was 8.9 mm. Nineteen clinical pregnancies were obtained, giving a pregnancy rate of 35% (19/54) per start cycle and 40% (19/47) per transfer cycle.

Conclusions: IVM of unstimulated immature oocytes for the treatment of women with various causes of infertility especially due to PCOS is an effective alternative method. The clinical pregnancy rate of 40% (19/47) is similar to that by conventional in vitro fertilization treatment in our unit.