O-301 Progesterone Primed Ovarian Stimulation (PPOS) for DuoStim combined with PGT-A in poor prognosis patients: a valuable strategy
Authors: Pittana E , Cimadomo D , Innocenti F , Colamaria S , Argento C , Giuliani M , Ruffa A , Petrone P , Trabucco E , Campitiello M  R , Guido M , Ferrero S , Rienzi L , Ubaldi F  M , Vaiarelli A 
Published: July 2024

Abstract

Study question
Is PPOS rather than conventional GnRH-antagonist a valid strategy in DuoStim protocols?

Summary answer
PPOS-DuoStim and conventional-DuoStim showed similar mean euploid blastocyst rate (EBR) per inseminated metaphase-II (MII) oocytes.

What is known already
DuoStim (double stimulation in the same ovarian cycle) is an efficient strategy to increase the number of oocytes retrieved and embryos obtained in the shortest possible timeframe. PPOS is based on the use of exogenous oral progesterone to prevent LH surge during ovarian stimulation (OS). The effectiveness and safety of PPOS have been consistently reported across the last years, supporting it as a clinically-valuable OS protocol. To date, no evidence exists about PPOS application in DuoStim protocols and its association with oocyte competence, defined as EBR per MII-oocytes.

Study design, size, duration
Retrospective study involving 138 PPOS-DuoStim and 138 matched conventional-DuoStim patients treated at a single clinic between 2021 and 2022 and collecting ≥1 MII-oocyte after both stimulations. Matching was based on maternal age (40.3±2.7 years), number of oocytes collected after the I-stimulation (5.8±3.6 years), and sperm quality (66% normozoospermic). The primary outcome was the EBR per MII-oocytes. All intermediate embryological and clinical outcomes were also compared. Sub-analyses among I- and II-Stimulations were also conducted.

Participants/materials, setting, methods
DuoStim entailed the same protocol in I- and II-Stimulations with FSH 300IU/day+LH 150IU/day, 5 days spanning the two stimulations and GnRH-agonist to trigger ovulation. The only difference between PPOS-DuoStim and conventional-DuoStim was the administration of medrossiprogesterone acetate10mg/day orally from the first day of stimulation versus flexible GnRH-antagonist from the day the follicles reached a diameter of 13-14 mm. The same laboratory procedures were applied: ICSI, trophectoderm biopsy, comprehensive-chromosome-testing to report uniform aneuploidies and vitrified-warmed single-embryo-transfers.

Main results and the role of chance
The patients in the two groups were comparable for ovarian reserve markers, BMI, and duration of infertility. All data were comparable in conventional-DuoStim and PPOS-DuoStim (Mann-Whitney U tests were conducted): (i) overall fertilization rate per inseminated MII-oocytes were 73.1±23.2% versus 76.8±17.8% (p = 0.143), (ii) overall blastulation rate per 2PN-zygotes were 46.6±30.4% versus 45.7±25.1%(p = 0.797), (iii) overall euploidy rates per biopsied blastocysts were 24.1±30.9% versus 25.4±31.3%(p = 0.956), (iv) EBR per inseminated MII-oocytes were 9.6±17% versus 9.2±12.7% (p = 0.735). The data among only I- and II-stimulations were also similar. When comparing I- versus II-stimulations, paired t-tests highlighted longer II-stimulations (11±1.9 vs11.6±1.9 days, p = 0.001), resulting in larger cohorts of MII-oocytes (4.3±2.8 vs 5.2±3.3, p &lt; 0.001) with comparable EBR per MII-oocytes (9.7±20.2% vs 11.6±16.2%, p = 0.233), thereby eliciting larger cohorts of euploid blastocysts (0.5±0.07 vs 0.7±0.09, p = 0.005). These data were confirmed also among conventional-DuoStim and PPOS-DuoStim study arms only. From a cycle perspective, among the 138 conventional-DuoStim couples, 31 (22%), 44 (32%) and 59 (43%) obtained ≥1 euploid blastocyst after I-stimulation, II-stimulation and overall, respectively. The same figures among the 138 PPOS-DuoStim were 36 (26%), 44 (32%) and 63 (46%), respectively. No statistical difference was reported (Fisher’s exact test=0.716).

Limitations, reasons for caution
Retrospective single center design. The current sample size should be doubled in order to reach a 80%-power with a 5%-α to exclude a 5% two-sided difference in the primary outcome. Patients’ compliance and discomfort, as well as clinical, gestational, and perinatal outcomes and cost-effectiveness analyses are needed.

Wider implications of the findings
PPOS is valuable in unconventional-OS protocols entailing freeze-all, like DuoStim with PGT-A. Future studies should assess if PPOS-DuoStim, by decreasing the number of injections and scans, may improve patient compliance and decrease OS discomfort. Any putative impact on follicular recruitment and oocyte yield should also be determined.

Trial registration number
not applicable