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Abstract Study question Are there differences in clinical and morphokinetic parameters of embryos obtained from fresh egg donation cycles using GnRH antagonist versus PPOS on same donor? Summary answer Lower number of oocytes retrieved and faster early morphokinetics parameters were observed in PPOS protocol. What is known already Controlled ovarian hyperstimulation (COH) is a crucial step in assisted reproduction treatments and the ideal protocol should be chosen according to the patient’s profile, based on literature results, intending to achieve high effectiveness. The use of PPOS in ovarian stimulation protocols is getting attention because of its safety, efficacy and proved to be patient friendly and an economical alternative to avoid premature LH surge. In the last years, morphokinetics parameters started to be considered in embryo classification and selection, as they correlate to embryo implantation potential. Here, morphokinetics parameters were compared from two different COH in donated oocyte cycles. Study design, size, duration Case-control study including cycles from 10 oocyte donors and 20 recipient patients, whose embryos formed with fresh oocytes were cultured in a time-lapse system (Embryoscope® Plus), in a single private IVF center between Jun/2020 and Oct/2022. Each donor were submitted to two cycles: first stimulation with standard GnRH antagonist (ant) short protocol (group A) and in a posterior cycle: a second stimulation with progesterone (PPOS protocol with dydrogesterone, group B). Participants/materials, setting, methods All donors used menotropin for COH (doses adjusted according to patient’s profile). Group A started GnRh ant with follicle above 14 mm. On group B, dydrogesterone 10 mg was started on the first day of COH and maintained until the day of ovulation trigger, which was performed with GnRH agonist. Clinical and morphokinetics parameters were compared. Paired t-test, t-test or Mann-Whitney were used properly, values of p 0.05 were considered significant. Main results and the role of chance A total of 70 blastocysts were analyzed, 39 from group A and 31 from group B. The following morphokinetics parameters were annotated: time of PN fading (tPNf), time to two cells (t2), three cells (t3), four cells (t4), five cells (t5), eight cells (t8), time to morula (tM), time to blastulation (tB) and KIDScoreTM. Statistically significant differences were observed for tPNf: group a) 24,01 ± 3,28h versus b) 22,59 ± 2,48h, p = 0,0484, t2: a) 26,30 ± 3,24h versus b) 24,76 ± 2,27h, p = 0,0211; t3: a) 37,04 ± 4,44h versus b) 35,53 ± 2,93, p = 0,0347 and t4: a) 38,38 ± 5,15h versus b) 36,05 ± 3,32h, p = 0,0152. Clinical characteristics of the donors were also analyzed: age, body mass index (BMI), total gonadotropin dose, antral follicular count (AFC), follicle stimulating hormone (FSH), basal hormone levels, follicle count, oocyte pick-up (OPU), altered oocytes, number of germinal vesicles, metaphase I (MI) and metaphase II (MII) oocytes. Differences were observed only between two clinical aspects: patients’ age: a) 24,2 ± 3,6 versus b) 25,0 ± 3,3, p = 0,0031 and OPU: a) 23,3 ± 9,1 versus b) 18,6 ± 8,3, p = 0,004, however both variables does not seem to affect embryo formation potential. Limitations, reasons for caution The results should be interpreted with caution due to the limitations of evaluate a small dataset of donors, resulting in low number of embryos in each group of protocols for analysis. Wider implications of the findings In this case-control study, a lower number of oocytes retrieved and faster early morphokinetics times were observed in PPOS compared to antagonist protocol. The implications of these differences still need further data analyses to compare if these findings can change clinical outcomes. Trial registration number Not applicable.
Domingues et al. (Mon,) studied this question.