Comparison of fixed and flexible progestin-primed ovarian stimulation in women classified in patient-oriented strategies encompassing individualized oocyte number (POSEIDON) group 4

This study aimed to compare the fixed and flexible protocols for progestin-primed ovarian stimulation (PPOS) in poor ovarian responders.

This retrospective study included 95 poor ovarian responders classified using the Patient-Oriented Strategies Encompassing Individualized Oocyte Number group 4 criteria. Treatment involved assisted reproductive medicine using fixed and flexible PPOS protocols at Shiga University of Medical Science between July 2019 and August 2023. PPOS cycles were assigned to the fixed and flexible groups at the discretion of attending physicians. The results of assisted reproductive medicine were compared between groups.

The fixed and flexible groups included 68 and 27 patients, respectively. The flexible group obtained more retrieved oocytes and two pro-nuclei than the fixed group, without an early luteinizing hormone surge. Multiple linear regression analysis demonstrated that differences in protocols and anti-müllerian hormone (AMH) levels were related to the number of retrieved oocytes. The differences in protocols were more strongly correlated with the number of oocytes than with the AMH levels.

Among poor ovarian responders, the flexible PPOS protocol provided more retrieved oocytes than the fixed PPOS protocol, possibly because the total dosage of progestins was lower in the flexible group and progestins were not administered at the time when ovarian stimulation was initiated.