To compare cumulative live birth rate according to the rate of use ofmetaphase II (MII) oocytes in conventional ovarian stimulation protocols for in vitro fertilization (IVF) or intracytoplasmic sperm injection. Methods: In a cohort study, patients aged 18–38 years undergoing their first IVF treatment at one US center were enrolled between February 1, 2009, and August 31, 2013. Ovarian response was categorized by the yield of MII oocytes (low: 1–2; intermediate: 3–6; high: ≥7). The main outcome measure was cumulative live birth rate over a 6-month period. Results: Among 250 participants, 3240 oocytes (mean ± SEM 12.96 ± 0.50) were retrieved and there were 152 (60.8%) live births. Overall, 172 (68.8%) participants had a high oocyte yield, 61 (24.4%) an intermediate yield, and 17 (6.8%) a low yield. The cumulative live birth rate was 58.8% (10/17) in the low-yield group, 55.7% (34/61) in the intermediate-yield group, and 62.8% (108/172) in the high-yield group (P = 0.35). Conclusion: In conventional ovarian stimulation, live birth rate is not affected by the ovarian response. Whether oocytes produced from a low ovarian response are biologically more effective than oocytes obtained from a high ovarian response remains to be determined.Read More