Hernandez-Nieto C, Lee JA, Alkon-Meadows T, et al. - Researchers investigated the influence of a late follicular phase progesterone rise (LFPE) during controlled ovarian hyperstimulation (COH) on embryonic competence and reproductive potential in thaw cycles of preimplantation genetic testing for aneuploidy (PGT-A) screened embryos. From September 2016 to March 2020, they conducted a retrospective cohort analysis in a single, academic ART center. Among 5,244 COH analyzed cycles for IVF/PGT-A, 5,141 were included in the analysis. Trophectoderm biopsy and PGT analysis were performed on a total of 23,991 blastocysts. Additionally, they evaluated the clinical IVF outcomes of 5,806 single euploid FET cycles. Division of the cohorts in two groups was done: Group 1: oocytes retrieved from cycles with normal P levels during ovulation trigger (P ≤ 2.0 ng/ml); Group 2: oocytes retrieved after cycles in which LFPE was noted (P > 2.0 ng/ml). Comparison was performed between 4,925 cycles in Group 1 and 216 cycles on Group 2. Per finding, LFPE, utilizing a progesterone cutoff value of 2.0 ng/ml, is neither linked with impaired embryonic development, elevated rate of embryonic aneuploidy, nor with compromised implantation and pregnancy outcomes following a euploid frozen embryo transfer cycle.