Optimal numbers of mature oocytes to produce at least one or multiple top-quality day-3 embryos in normal responders

OBJECTIVE: We attempted to identify the optimal cutoff numbers of mature oocytes that would produce at least one or multiple top-quality (grade A) day-3 embryos in normal responders undergoing stimulated in vitro fertilization (IVF) cycles. METHODS: We selected 210 fresh IVF cycles performed in 170 infertile women at a single center from January 2014 to November 2019. Four to 14 (total) oocytes were obtained in all cycles after conventional ovarian stimulation. A receiver operating characteristic curve analysis was performed to find the moderate and extreme cutoff numbers of mature oocytes that would produce ≥ 1, ≥ 2, ≥ 3, ≥ 4, and ≥ 5 top-quality embryos. RESULTS: The cutoff number of mature oocytes was significantly correlated with the number of top-quality embryos (r = 0.467, p= 0.000). The moderate cutoff number of mature oocytes was ≥ 3, ≥ 5, ≥ 5, ≥ 6, and ≥ 6 for obtaining ≥ 1, ≥ 2, ≥ 3, ≥ 4, and ≥ 5 top-quality embryos, respectively. The extreme cutoff number of mature oocytes was ≥ 9, ≥ 9, ≥ 10, ≥ 10, and ≥ 11 for obtaining ≥ 1, ≥ 2, ≥ 3, ≥ 4, and ≥ 5 top-quality embryos, respectively. CONCLUSION: We present the optimal cutoff numbers of mature oocytes that would yield ≥ 1, ≥ 2, ≥ 3, ≥ 4, and ≥ 5 top-quality embryos with 95% specificity. Our findings could help infertility clinicians to set target mature oocyte numbers in women undergoing stimulated IVF cycles.