PROGESTERONE-PRIMED OVARIAN STIMULATION COMPARED WITH GNRH ANTAGONIST IN FERTILITY PRESERVATION CYCLES FOR MEDICAL REASONS.

To minimize the impact that gonadotoxic chemotherapy, pelvic radiotherapy, and ovarian surgery may have on the woman`s future reproductive potential, it is increasingly common to perform fertility preservation cycles.

The utilization of oral progestins instead of GnRH antagonists is increasingly prevalent in ovarian stimulation in this type of treatments.

Fifty-seven patients undergoing fertility preservation treatments at La Paz University Hospital were analyzed. Descriptive parameters such as age, BMI, AMH levels, type and dosage of gonadotropins, type of gestagen, stimulation days, number of oocytes obtained in follicular aspiration, and cryopreserved mature oocytes were assessed.

16 patients had undergone a prior cycle with GnRH antagonist. The results of the 32 preservation cycles were compared, employing a Student t-test for the variables number of oocytes retrieval, and the number of cryopreserved mature oocytes (stimulation days and gonadotropin dosage).

Results:The mean age was 29.4 years(range:16-38), BMI 22.3(14.2-34.2), and AMH 1.98ng/ml(0.03-8.2). The mean cycle duration was 11.7 days(9-17) with a total gonadotropin dosage of 3178 IU(1500-4875), and a mean daily dosage of 271 IU. The most frequently used progestin was desogestrel(89.5%), followed by AMP(7%), Drospirenone(1.8%), and levonorgestrel(1.8%). The indications for preservation were endometriosis(61.5%), oncologic causes(19.3%), transgender boys(8.8%), genetic reasons(5.3%), chronic disease(1.8%), and low ovarian reserve(3.5%).

We obtained 9.8 oocytes on the day of puncture(0-41), and 8 mature oocytes(0-37) were developed. In the cycles compared with antagonist use, when employing oral progestins, an average of 6.69 oocytes were retrieved versus 6.19(p=0,37); and 4.69 mature oocytes were collected versus 4.75(p=0,48). While in 56.25% of cycles(n=9), more mature oocytes were obtained in the antagonist cycle, the results are not statistically significant. Statistically significant differences were found in the duration(10.88 days with progestins and 12.63 with antagonist, p=0.002) and total gonadotropin dosage(3128.13 IU with progestin and 3506.25 with antagonist, p=0.016).

Conclusion:There were no significant differences in the outcomes of fertility preservation cycles using oral progestins versus antagonist; however, the cycles with gestagen exhibited shorter durations and lower gonadotropin dosages. Although randomized studies with larger sample sizes are necessary to draw definitive conclusions, oral progestins inhibition could potentially serve as an effective alternative with reduced cost and greater patient comfort.