2024-11-0920221464-727310.1080/14647273.2020.17940602-s2.0-85088106211http://dx.doi.org/10.1080/14647273.2020.1794060https://hdl.handle.net/20.500.14288/14817The aim of this retrospective cohort study was to compare the effectiveness of the new flexible progestin primed ovarian stimulation (fPPOS) protocol with the flexible gonadotropin-releasing-hormone antagonist (GnRH-ant) protocol in women with decreased ovarian reserve (DOR). Twenty-seven women who underwent fPPOS and 54 age-matched women who received GnRH-ant for pituitary suppression were included in the study. All women had DOR and underwent oocyte cryopreservation. Three-hundred IU/day FSH was started on cycle day 2-3 and 0.25 mg/day GnRH-ant or 10 mg/day medroxyprogesterone acetate was started when the leading follicle reached 14 mm or serum oestradiol level was >= 200 ng/mL. The median duration of stimulation, day of commencing pituitary suppression and duration of suppression were similar in both groups, with 8, 5, and 5 days, respectively. The median number of cumulus-oophorous complexes (4.0 vs 5.5), metaphase-two oocytes (3 vs 4), the total number of oocytes cryopreserved (3.0 vs 4.5), and oocyte maturation rates (0.67 vs 0.70) were similar between the fPPOS and GnRH-ant groups, respectively. There was one case of premature ovulation in the fPPOS group and none in the GnRH-ant group (p = 0.91). In conclusion, fPPOS may be used in women with DOR without compromising the number of oocytes retrieved and seems a viable alternative to the flexible GnRH-ant protocol.ObstetricsGynecologyReproductionBiologyJournal Article1742-81495490328000018696