Endogenous luteinizing hormone concentration and IVF outcome during ovarian stimulation in fixed versus flexible GnRH antagonist protocols: An RCT

Background: Luteinizing hormone (LH) is essential for normal follicular development and oocyte maturation. In particular, fluctuations of LH during the follicular phase have a significant impact on morphological and functional changes of the oocyte and determine its meiotic status and ability to be fertilized. Objective: This prospective randomized controlled trial examined effects of endogenous follicular phase LH levels on oocyte maturity and IVF outcomes in fixed vs. flexible in vitro fertilization. Materials and Methods: Normo-ovulatory women age <39 yr (n=213) were randomized to fixed or flexible gonadotrophin-releasing hormone (GnRH) antagonist protocols. Follicular phase LH, estradiol, and progesterone profiles were measured. Oocytes retrieved, implantation rate, and pregnancy rate were compared between the two groups. Results: LH profiles were similar in both protocols. A lower trend of LH values at the end of ovarian stimulation correlated significantly with a higher pregnancy rate, regardless of protocol (p=0.02). Estradiol levels were statistically different with respect to time points within treatment groups (p<0.0001), but not between groups (p=0.43), or pregnancy outcomes (p=0.2595). Progesterone profiles were similar between groups. No differences were found in retrieved oocytes numbers, fertilization rate or embryos obtained. Significantly, younger age and a higher number of antral follicles were correlated with positive results. Conclusion: Fixed and flexible GnRH antagonist protocols did not produce an oscillation of endogenous LH values correlated to the outcome of ovarian stimulation.