P-130 Progesterone-primed cycles result in slower embryos without compromising the implantation potential, with the advantage of oral administration and potential cost reduction: A time-lapse imaging study

Abstract Study question Could exogenous progestin replace the use of an antagonist GnRH (GNRH-antagonist) without any effects on embryo morphokinetics and implantation rate in freeze-all cycles? Summary answer Exogenous leads to slower development increased cyclés cancellation rate, with when compared cycles using GnRH-antagonist. What is known already Improvements cryopreservation techniques associated expansion elective-single transfer have steadily deferred transfers. This gives opportunity break away from standard sequence stimulation–retrieval–transfer, consider new strategies for pharmacological control follicle growth. Usual ovarian stimulation regimens analog prevent LH surge premature ovulation. Since progesterone able block remains whether may analogue compromising development, followed by cryopreservation. design, size, duration cohort study, performed a private university-affiliated IVF center, Mar/2019 - Mar/2021, included 288 ICSI its 2,768 respective embryos. Patients were age matched, according age, into groups depending protocol used surge: Progestin-Primed-Group (n = 144 1,360 embryos) GnRH-Antagonist-Group 1,408 embryos). Embryos cultured time-lapse imaging incubation system (TLI) among Participants/materials, setting, methods Evaluated kinetic markers timing pronuclei appearance (tPNa) fading (tPNf), two, three, four, five, six, seven, eight cells (t2 t8), morulation (tM), start blastulation (tSB) (tB). Durations second (t3-t2) third (t5-t3) cell (cc2 cc3) complete synchronous divisions s1 (t2-tPNf), s2 (t4-t3), s3 (t8-t5) also calculated. The KID-Score ranking, laboratorial clinical outcomes evaluated. Main results role chance Mean maternal paternal ages 37.0 ± 3.8 39.0 6.4 years old. Slower tPNa (6.2 0.2 vs. 7.0 0.2, p 0.008), t2 (27.2 0.3 26.2 0.3, 0.045), t7 (56.4 54.7 0.5, 0.046), tM (89.3 0.8 87.1 0.6, tSB (101.5 110.8 0.1, 0.012), tB (111.0 108.5 0.7, 0.034), observed embryos derived Progestin-Primed cycles. Similar tPNf, t3, t4, t5, t6, t8, cc2, cc3, s1, s2, groups. No significant differences noted Kid-score D5, number aspirated follicles, retrieved oocytes, oocyte yield, mature rates fertilization, blastocyst formation. cancelation (15.7% 2.0%, 0.004) (63.1% 6.1 44.4% 6.3, Progestin-Primed-Group, however no cumulative pregnancy (64.4% 49.0%, 0.104) miscarriage (2.6% 8.6%, 0.554) GnRH-Antagonist groups, respectively. expense ovulation prevention was U$318.18, while progestins U$ 11.05 sufficient inhibit surge. Limitations, reasons caution study has limitations, such as retrospective design small sample size. Wider implications findings Despite potential cost reduction, high progestin-protocol cannot be ignored. Delayed due freeze-only approach inconvenient. Before considering protocols prevention, pros cons must carefully Trial registration N/A