Benefit of FSH priming of women with PCOS to the in vitro maturation procedure and the outcome: a randomized prospective study

The aim of this study was to determine whether the rates of in vitro oocyte maturation, fertilization and cleavage, as well as implantation rate and pregnancy rate, could be improved by low-dose priming with FSH in vivo before retrieval of immature oocytes in patients with polycystic ovary syndrome (PCOS). From March 1998 to June 2000, a total of 28 women underwent 36 completed treatment cycles, randomized sequentially in one of two groups. Women in group 1 (n = 12 cycles) received no stimulation and women in group 2 (n = 24 cycles) received 150 iu recombinant FSH day(-1) for 3 days, initiated on day 3 after menstruation. Aspiration was performed transvaginally between day 9 and day 17 in the unstimulated group and on day 8 or day 9 in the FSH-primed group after FSH deprivation for 2 or 3 days. All cumulus-enclosed oocytes of healthy appearance were matured in culture medium (TCM-199) in vitro for 28-36 h before intracytoplasmic sperm injection (ICSI). After oocyte retrieval the women were given oestradiol (6 mg day(-1)) and progesterone administration (300 mg day(-1)) was initiated 2 days later. Suitable embryos (maximum two embryos) were transferred on day 3 after ICSI. The percentage of oocytes reaching metaphase II was significantly higher (P < 0.05) in the FSH-primed group (59%, 92/156) compared with the non-primed group (44%, 36/81). There were no significant differences in the rates of oocyte fertilization and cleavage between these groups. No pregnancies were obtained in group 1 (0%, 0/12), whereas seven clinical pregnancies were obtained in group 2 (29%, 7/24) (P < 0.05). In group 2, 37 embryo transfers resulted in eight implantations (21.6%). Three healthy singleton children have been born at term; the remaining pregnancies ended with spontaneous abortions in the first trimester. These results indicate that priming with recombinant FSH before harvesting of immature oocytes from patients with PCOS may improve the maturational potential of the oocytes and the implantation rate of the cleaved embryos.