P-683 Progestins vs flexible GnRH antagonist for LH suppression during controlled ovarian stimulation in POSEIDON groups 3 and 4 patients: Analysis of effectiveness and cycle outcomes
Authors: Parhar P , Addagatla P , Rao D , Chaitanya K 
Published: July 2024

Study question

How do cycle outcomes differ between controlled ovarian stimulations using progestins vs ﬂexible GnRH antagonists for LH suppression in women with diminished ovarian reserve (DOR)?

Summary answer

While progestin use is associated with significantly higher blastocyst rate than GnRH antagonists in POSEIDON group 4, the latter gives better results in group 3.

What is known already

Controlled ovarian stimulation (COS) in patients with DOR carries the additional risk of premature luteinizing hormone (LH) surge and ovulation.GnRH antagonists are popular for LH suppression in COS because of their convenient, quicker onset of action, flexibility to use GnRH agonist as a trigger and continue as double stimulation, allowing rapid pooling of embryos. Ease of oral administration, combined with cost-effectiveness and retention of all the benefits of GnRH antagonists makes progestins an attractive alternative to GnRH antagonists for COS in patients with DOR who often need multiple stimulation cycles to enable the pooling of embryos.

Study design, size, duration

An open-label, multicentric, randomized controlled study was conducted over 1 year from January 2023 to December 2023. 140 women aged 21- 42 years and with AMH &lt;1.2 ng/dl were randomized into 2 groups in a 1:1 ratio, using either oral progestins or GnRH antagonists for LH suppression. The two groups were further comparative analyzed under POSEIDON 3 and 4 subgroups. Those with BMI &gt;40kg/m2 and with partners having severely compromised semen parameters were excluded.

Participants/materials, setting, methods

In Group A (PPOS): Medroxyprogesterone acetate 10 mg orally was given daily with gonadotropins (hMG 300- 375 IU) from cycle day 2 until trigger. In Group B (Antagonist), patients had daily GnRH antagonist, cetrotide 0.25 mg, subcutaneous administration started when the dominant follicles reached 12-14 mm size during controlled ovarian stimulation. This was continued until the trigger. Following oocyte retrieval and ICSI, embryos were cultured until D5 and vitrified fortransfer in subsequent HRT cycles.

Main results and the role of chance

Patients in Group A, using PPOS, were noted to have significantly better fertilization rates than those in Group B, using flexible GnRH antagonists (0.82 + 0.2 vs 0.66 + 0.4, p-value &lt;0.01). Though the number of top-quality embryos (TQE) frozen was not significantly different between groups A and B (p-value = 0.44), a significant difference in the outcome was noted when comparatively analyzed under the subgroups of POSEIDON groups 3 and 4. While patients in POSEIDON group 4 got significantly more top-quality embryos (TQE) when progestins were used for LH suppression (1 + 0.11 vs 0.77 + 0.41, p-value &lt;0.01), those in POSEIDON group 3 got significantly more top-quality embryos when GnRH antagonist was used (0.94 vs 2, p-value &lt;0.01). Patients in Group A and B were found to have no significant difference in the following outcomes: incidence of premature LH surge (4.3% vs 7.1%, p value= 0.71), number of days of stimulation (10.26 + 2.18 vs 10.26 +2.94, p value= 0.99), total gonadotropin dosage used (3448.64+ 1007.98 vs 3087.41 + 1260.56, p value=0.06), total number of oocytes retrieved (5.84 + 3.3 vs 4.9 + 3.4, p value=0.09) and total cycle cancellation rate (30.1% vs 35.7%, p value= 0.11).

Limitations, reasons for caution

The small sample size of the cases limits the current statistical power of the study. The results being encouraging need to be confirmed in a larger patient population and followed for a longer duration to enable calculation of implantation and clinical pregnancy rates for all patients.

Wider implications of the findings

Oral progestins are an effective and cheaper, patient-friendly alternative to injectable GnRH antagonists during COS in women with DOR. Considering the significantly higher TQEs formed, PPOS can be preferred in older, POSEIDON group 4 patients, whereas flexible GnRH antagonist protocol can be our choice in the younger, POSEIDON group 3.

Trial registration number

Not applicable