Comparison of fixed and flexible progestin-primed ovarian stimulation protocols to prevent premature luteinization in patients with diminished ovarian reserve

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

PURPOSE

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

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Progestin-primed ovarian stimulation

PURPOSE OF REVIEW

The use of progestins as pituitary suppressors has increased progressively, along with more detailed indications for their use, thereby consolidating an alternative approach to the personalization of ovarian stimulation.

RECENT FINDINGS

Based on the ability of progesterone to inhibit ovulation, progestins have been used in ovarian stimulation (OS) follicular protocols to prevent a luteinizing hormone surge in patients undergoing in vitro fertilization (IVF), as an alternative to gonadotropin-releasing hormone (GnRH) analogue administration. This review explores the different types of progestogen protocols and their efficacy depending on the type of population or reproductive procedure in which they are administered and in comparison with that of GnRH analogues. Their effect on oocytes and embryos and their safety and cost-effectiveness are also analyzed.

SUMMARY

Progestins have proven their effectiveness as a gonadotropin adjuvant in terms of ovarian response, reproductive outcome, and safety. In addition, they offer the convenience of oral administration and a lower cost than GnRH analogues. Whereas oocytes or embryos should be vitrified as it displaces the receptive period with the consequent asynchrony between embryo and endometrium. The evidence endorses progestins as a more friendly approach to OS, especially when frozen-thawed embryo transfer is planned.

Progestin-primed ovarian stimulation: for whom, when and how?

Progestin-primed ovarian stimulation (PPOS) is being increasingly used for ovarian stimulation in assisted reproductive technology. Different progestins have been used with similar success. The available studies suggest a similar response to ovarian stimulation with gonadotrophin-releasing hormone (GnRH) analogues. Any differences in the duration of stimulation or gonadotrophin consumption are minor and clinically insignificant. PPOS has the advantage of oral administration and lower medication costs than GnRH analogues. As such it is clearly more cost-effective for fertility preservation and planned freeze-all cycles, but when fresh embryo transfer is intended PPOS can be less cost-effective depending on the local direct and indirect costs of the additional initial frozen embryo transfer cycle. Oocytes collected in PPOS cycles have similar developmental potential, including blastocyst euploidy rates. Frozen embryo transfer outcomes of PPOS and GnRH analogue cycles seem to be similar in terms of both ongoing pregnancy/live birth rates and obstetric and perinatal outcomes. While some studies have reported lower cumulative live birth rates with PPOS, they have methodological issues, including arbitrary definitions of the cumulative live birth rate. PPOS has been used in all patient types (except progesterone receptor-positive breast cancer patients) with consistent results and seems a patient friendly and cost-effective choice if a fresh embryo transfer is not intended.