Effect of GnRH Agonist in FET

Assisted reproductive technologies (ART), particularly intracytoplasmic sperm injection (ICSI) with frozen embryo transfer, have significantly improved the outcomes of infertility treatment over the past decades. Despite these advances, implantation failure and suboptimal pregnancy rates remain important challenges. One of the critical factors influencing the success of embryo implantation is adequate luteal phase support, which ensures proper endometrial receptivity and maintenance of early pregnancy. (1_3) Progesterone supplementation has long been established as the standard method for luteal phase support in frozen ICSI cycles. It plays a fundamental role in transforming the endometrium into a receptive state suitable for embryo implantation and sustaining early gestation. However, despite its widespread use, pregnancy outcomes are not optimal in all cases, suggesting the need for additional or alternative therapeutic strategies to enhance reproductive success.(1_3) Recently, gonadotropin-releasing hormone (GnRH) agonists have gained increasing attention as a potential adjunct in luteal phase support protocols. It has been proposed that GnRH agonists may exert beneficial effects through multiple mechanisms, including stimulation of endogenous luteinizing hormone (LH) secretion, improved corpus luteum function, and enhanced progesterone production. Additionally, emerging evidence suggests a possible direct effect on the endometrium and embryo-endometrial interaction, which may further improve implantation potential.(4-7) Despite promising findings from several randomized controlled trials and meta-analyses, the role of GnRH agonists in luteal phase support remains controversial. Some studies have demonstrated improved implantation and clinical pregnancy rates, while others have reported no significant benefit compared to conventional progesterone therapy alone. This inconsistency is particularly evident in frozen ICSI cycles, where hormonal dynamics differ from fresh cycles.Therefore, further well-designed prospective studies are required to clarify the effectiveness of GnRH agonists in luteal phase support and to determine their potential role in improving reproductive outcomes

• GnRH agonist (Drug), also known as triptofem0.1 amp: women undergoing frozen ICSI cycles receiving progesterone + GnRH agonist for luteal phase support.

Primary outcomes

• Clinical pregnancy rate [basline]: Presence of ≥1 gestational sac with fetal heartbeat on TVS at 6-7 weeks per embryo transfer.

Secondary outcomes

• Implantation rate [basline]: Number of gestational sacs / Number of embryos transferred x100
• Ongoing pregnancy rate [basline]: Viable pregnancy ≥12 weeks gestation per ET
• Early miscarriage rate [basline]: Pregnancy loss <12 weeks after clinical pregnancy diagnosed
• . Live birth rate per ET [basline]: . Live birth rate per ET
• Side effects [basline]: Injection site reaction, headache, vaginal bleeding

Sex: Female, ages: 20 Years to 39 Years, accepts healthy volunteers

Inclusion Criteria:

* 1\. Age 20-39 years 2. Undergoing HRT-FET cycle 3. ≥1 good quality embryo available , Gardner ≥3BB 4. Endometrial thickness ≥7mm on day of progesterone start 5. BMI 18-35 kg/m² 6. First or second FET cycle 7. Written informed consent

Exclusion Criteria:

* 1\. History of recurrent implantation failure ≥3 failed embryo transfers 2. Severe endometriosis Stage III-IV by ASRM 3. Uterine anomalies, submucous fibroid, or severe adenomyosis distorting cavity 4. History of recurrent pregnancy loss ≥2 consecutive 5. Contraindication or hypersensitivity to GnRH agonist 6. PGT-A cycles 7. Donor oocyte cycles

• Results publication: Liu Y, Huang K, Chen C, Wen L, Lei M, Guo Y, Tang B. Effect of luteal-phase GnRH agonist on frozen-thawed embryo transfer during artificial cycles: a randomised clinical pilot study. Front Endocrinol (Lausanne). 2023 Jun 9;14:1098576. doi: 10.3389/fendo.2023.1098576. eCollection 2023. PMID 37361538
• Results publication: Li S, Li Y. Administration of a GnRH agonist during the luteal phase frozen-thawed embryo transfer cycles: a meta-analysis. Gynecol Endocrinol. 2018 Nov;34(11):920-924. doi: 10.1080/09513590.2018.1480714. Epub 2018 Jul 11. PMID 29996682
• Results publication: Chang WS, Lin PH, Li CJ, Chern CU, Chen YC, Lin LT, Tsui KH. Additional single dose GnRH agonist during luteal phase support may improve live birth rate in GnRHa-HRT frozen-thawed embryo transfer cycle: a retrospective cohort study. BMC Pregnancy Childbirth. 2023 Mar 14;23(1):174. doi: 10.1186/s12884-023-05491-y. PMID 36918869