Serum stem cell factor assay in elderly poor responder patients undergoing IVF: A new biomarker to customize follicle aspiration cycle by cycle

In humans, stem cell factor (SCF), produced during follicular phase, may reflect a successful stimulation and oocyte maturation and so it may be a predictor of in vitro fertilization (IVF) outcome. An observational cohort study was conducted on 37 poor responders scheduled for fresh nondonor IVF/intracytoplasmic sperm injection treatment with standard controlled ovarian stimulation (COS) using recombinant follicle-stimulating hormone (rFSH; S-COS group). A total of 35 women received a second treatment using both rFSH and recombinant luteinizing hormone (rLH; LH-COS group). From 144 samples collected at pickup day, serum concentration of SCF (s-SCF) and follicular levels of SCF (f-SCF) were measured by enzyme-linked immunosorbent assay (ELISA) kit. No differences were observed between the 2 protocols in terms of both f-SCF and s-SCF levels. The comparison between f-SCF and s-SCF levels showed a strong linear correlation. The comparison between s-SCF levels and clinical outcomes showed a statistically significant correlation between both the number of metaphase II (MII) oocytes retrieved and the embryos obtained after fertilization. Cases with at least 3 MII oocytes showed s-SCF values >800 pg/mL, 2 MII oocytes >600 pg/mL, and 1 MII oocytes >400 pg/mL. In 100% of cases with s-SCF <400 pg/mL, no MII oocytes were recovered. All 5 pregnancies occurred in patients with s-SCF values >1000 pg/mL. The introduction of s-SCF assay in the management of poor-responder patients may contribute to solving the dilemma of whether to cancel or proceed with the stimulation cycle.