P-369 DuoStim could be a proper option for women seeking fertility preservation for non-medical reasons

Abstract Study question Is Duostim a suitable option for women who wish to preserve fertility for social reasons? Summary answer Providing the option of DuoStim is an efficient way to expand the cohort of vitrified oocytes in women seeking fertility preservation for non-medical reasons. What is known already A growing number of reproductive-age women are choosing to postpone motherhood, giving rise to the concept of reproductive autonomy. Numerous strategies aim to refine ovarian stimulation protocols. DuoStim, entailing dual ovarian stimulations and retrievals within one menstrual cycle, proves advantageous for those with diminished ovarian reserve or facing cancer. To our knowledge, this is the first study offering DuoStim for social preservation. Study design, size, duration Retrospective controlled case-control study conducted with paired follicular phase stimulation (FPS) and luteal phase stimulation (LPS) derived cohorts of oocytes collected in the same ovarian cycle (DuoStim). The study included 160 patients aged 36.85 ± 3.3 years old, who underwent DuoStim for social egg freezing from October 2018 to September 2023. The primary outcome was the number of MII oocytes retrieved per cycle and secondary outcomes included stimulation duration and gonadotropin dose. Participants/materials, setting, methods FPS and LPS were performed using the same daily dose of recombinant gonadotropins in an antagonist protocol. Oocyte retrieval was performed 36 hours after triggering with gonadotropin-releasing hormone agonist triptorelin acetate (0,2 mg) after the FPS. Luteal phase stimulation protocol began on the 5th day after ovarian puncture using dual trigger, followed by a second oocyte retrieval. Mature oocytes were vitrified 2 hours later following the Kitazato® protocol. Main results and the role of chance Stimulation duration and gonadotropin dose were lower during Follicular Phase Stimulation (FPS) vs. Luteal Phase Stimulation (LPS) (10.8 ± 1.5 days vs. 13.0 ± 2.3, P < 0.05 and 2,487.9 ± 580.8 vs. 3,264.0 ± 942.7, P < 0.05). The number of retrieved oocytes was comparable between the two groups (4.78 ± 3.0 vs. 5.32 ± 3.7; P = 0.15). The mean number of MII oocytes acquired in the LPS group exceeded that in the FPS group (4.16 ± 3.0 vs. 3.58 ± 2.3; P = 0.054), indicating a tendency towards more MII oocytes in the LPS group without achieving statistical significance. A total of 110 patients (69.29%) obtained the same or a greater number of MII during the LPS compared to the FPS. Limitations, reasons for caution Although DuoStim is acknowledged as an option to obtain a greater number of eggs in certain situations, the evidence supporting its utility in social fertility preservation is still limited. It is crucial to recognize the inherent biases in observational retrospective studies. Wider implications of the findings DuoStim could be an advantage for women who live abroad or those who dispose of short periods of time for oocyte vitrification, also potentially reducing the drop-out rate. Trial registration number not applicable