Pretreatment with follicle stimulating hormone promotes the numbers of human oocytes reaching metaphase II by in-vitro maturation

The objective of this study was to investigate the effect of follicle stimulating hormone (FSH) priming on the in-vitro maturation (IVM) of human oocytes from healthy ovaries using a chemically defined culture system. Seventeen patients donating oocytes for research received a truncated course of 600 IU FSH over 5 days and a further control group of nine patients received no FSH treatment. Midfollicular phase cumulus-enclosed oocytes (n = 160) were aspirated from follicles less than or equal to 4 mm diameter under transvaginal ultrasound guidance and were cultured for 48 h in microdrops of medium containing 10 mIU/ml FSH and 100 mIU/ml human chorionic gonadotrophin (HCG). The results demonstrated that human oocytes will efficiently undergo IVM under serum-free conditions. After mild FSH stimulation, a greater number of cumulus-enclosed oocytes was collected, and following culture, a lower rate of degeneration was observed, Significantly more oocytes completed nuclear maturation to metaphase II following FSH stimulation (71.1 versus 43.5%), In conclusion, a truncated course of FSH stimulation in vivo improved the oocyte maturation rate in vitro, giving a mean of 4.8 +/- 0.7 metaphase II oocytes per patient compared with only 2.1 +/- 0.7 from control patients, thus yielding more mature oocytes for future IVF treatment.