Diminished intrafollicular estradiol levels in in vitro fertilization cycles from women with reduced ovarian response to recombinant human follicle-stimulating hormone

Objective: To correlate serum and intrafollicular E-2 levels in women receiving GnRH agonist and recombinant human (h)FSH for IVF. Design: Prospective study. Setting: Academic IVF center. Patient(s): Twenty-three nonhirsute ovulatory women. Intervention(s): In vitro fertilization cycles were classified as high- or low-normal response, according to whether the amount of recombinant hFSH administered was below or above, respectively, the mean recombinant hFSH given to all women combined. Serum bioactive LH and immunoreactive FSH were measured during pituitary desensitization preceding recombinant hFSH and repeated at oocyte retrieval. The first mature follicle aspirated from either ovary had a mean diameter > 15 mm. Main Outcome Measure(s): Serum and follicular fluid (FF) insulin, bioactive LH, immunoreactive FSH, and steroid levels. Result(s): Basal serum gonadotropin levels were comparable between female groups. Serum immunoreactive FSH levels. but not bioactive LH levels, at oocyte retrieval were greater in cycles of low-normal vs. high-normal response, whereas maximum serum E-2 levels and total oocyte counts were similar between both groups. Despite elevated FF immunoreactive FSH levels, FF E-2 was decreased in low-normal response cycles. Intrafollicular T and P also were decreased and increased, respectively, in cycles of low-normal response, although FF bioactive LH levels were comparable in both groups. Conclusion(s): Intrafollicular E-2 is decreased in cycles of reduced ovarian responsiveness to GnRH agonist and recombinant hFSH and is not predicted by maximal serum E-2 or number of oocytes retrieved. (© 2005 by American Society for Reproductive Medicine.)