Gerber RS, Fazzari M, Kappy M, et al. - Via this historical cohort study, researchers examined how both controlled ovarian hyperstimulation (COH) length and total gonadotropin (GN) dose individually and in concert affect live birth rates (LBR) in both fresh and freeze-all in vitro fertilization embryo transfer (IVF-ET) cycles. Searching the US national database from the Society of Assisted Reproductive Technology Clinic Outcome Reporting System from 2014 to 2015, they identified cases undergoing autologous GN stimulation IVF cycles with the use of GnRH antagonist–based suppression protocols where a single embryo transfer was conducted as part of a fresh IVF-ET cycle (fresh, n = 14,866) or the first frozen embryo transfer after a freeze-all cycle (frozen, n = 2,964), and not incorporating preimplantation genetic testing cycles. In both fresh and frozen cycles, they noted significant correlation of length of COH with total GN dose. They observed correlation of high total GN dose but not of prolonged COH with decreasing LBRs in fresh cycles, whereas there was no significant effect of any of the factor on LBR in frozen cycles. Whenever possible, minimization of the total GN dose should be considered in fresh autologous cycles, either by reducing the daily dose or by limiting the length of stimulation to improve LBRs. In freeze-all cycles, there appeared no adverse effect of using higher GN doses on the LBR of the first frozen embryo transfer. There appeared a likelihood of a negative impact of high total GN dose on the endometrium and/or oocyte/embryo unrelated to the length of stimulation. Total GN dose had differential effect on LBR in fresh and frozen cycles; this may imply a greater impact exerted on the endometrium rather than the oocyte.