Efficacy of Highly Purified Urinary FSH versus Recombinant FSH in Chinese Women over 37 Years Undergoing Assisted Reproductive Techniques

Background: Urine derived follicle-stimulating hormone (uFSH) contains a higher proportion of acidic isoforms, whereas recombinant FSH (rFSH) contains a higher proportion of less-acidic isoforms. Less-acidic isoforms have a faster clearance, and thus a shorter half-life than the acidic FSH isoforms. The slow clearance of the acidic isoforms has a longer half-life and higher biological activity. This study was designed to determine whether uFSH or rFSH is more effective in older Chinese women undergoing assisted reproductive techniques (ART). Materials and Methods: This is a prospective, randomized, controlled cohort study. A total of 508 Chinese women over 37 years were randomized into two following study groups for their in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles: i. group A (n=254) were treated with rFSH, and ii. group B (n=254) were treated with uFSH. Both groups were suppressed with a gonadotropin-releasing hormone (GnRH) analogue using a long down-regulation protocol. The main outcomes for comparison were days of stimulation, estradiol (E2) on the day of human chorionic gonadotropin (hCG) administration, number of oocytes collected, amount of FSH used, quantity of FSH/oocyte, endometrial thickness at hCG day, M ? oocyte rate, 2PN zygote rate, grade ? embryo rate, number of embryos cryopreserved, pregnancy rate, implantation rate, abortion rate and the rate of no transferable embryos. Results: Twenty two cycles including 16 cycles with poor ovarian response and six cycles with ovarian hyperstimulation syndrome were cancelled. There were 243 cycles left in each group. The patients treated with uFSH had a significantly higher 2PN zygote rate (87.4 vs. 76.6%, p < 0.001), grade ? embryo rate (49.8 vs. 40.8%, p < 0.001) and endometrial thickness on day of hCG (11.8 mm vs. 11.2 mm, respectively, p=0.006) and a lower rate of no transferable embryos (1.2 vs. 5.3%, p=0.019) than women treated with rFSH. The other measures evaluated showed no statistically significant differences between groups (p > 0.05). Conclusion: This study showed that uFSH produced a significantly higher proportion of grade ? embryos than rFSH in older Chinese women and there was a significantly lower chance of no transferable embryos in uFSH cycles. The clinical efficacy of the two gonadotropins was equivalent.