Keywords: triptorelin, luteal phase support, ICSI, GnRH agonist

Introduction: Understanding Triptorelin

Triptorelin is a synthetic gonadotropin-releasing hormone (GnRH) agonist commonly used in reproductive medicine, particularly in assisted reproductive technologies (ART) such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). It plays a crucial role in regulating hormonal activity by stimulating or suppressing the release of key reproductive hormones — luteinizing hormone (LH) and follicle-stimulating hormone (FSH) — depending on the dosage and duration of administration.

In ART protocols, triptorelin is primarily used to suppress premature ovulation during controlled ovarian hyperstimulation (COH). However, recent studies have shown that it also offers significant benefits when administered during the luteal phase , especially in antagonist ICSI cycles.

How Does Triptorelin Work in the Body?

Triptorelin mimics the action of naturally occurring GnRH, which is produced by the hypothalamus to regulate the pituitary gland’s secretion of LH and FSH. When given in pulsatile low doses, triptorelin stimulates the release of these hormones. However, when administered continuously at higher doses, it causes down-regulation of GnRH receptors on the pituitary gland, ultimately reducing the production of LH and FSH.

This suppression is essential during ovarian stimulation to prevent a premature LH surge, which can lead to early ovulation and poor oocyte retrieval outcomes.

But beyond its use in the follicular phase, triptorelin has been found to enhance corpus luteum function when given during the luteal phase, increasing progesterone production and improving endometrial receptivity for embryo implantation.

The Importance of Luteal Phase Support in ICSI Cycles

The luteal phase is the second half of the menstrual cycle, following ovulation. During this time, the corpus luteum produces progesterone and estradiol, which are critical for preparing the endometrium for embryo implantation.

In ICSI cycles using GnRH antagonists , the natural production of LH may be suppressed, leading to reduced progesterone levels and an inadequate luteal phase. This can result in lower implantation rates and pregnancy outcomes.

To counteract this, luteal phase support (LPS) is provided through exogenous progesterone supplementation. Recent clinical evidence suggests that adding triptorelin 0.1 mg six days after oocyte pickup (OPU) significantly enhances luteal function by stimulating the pituitary to release LH and FSH, which in turn boosts steroid synthesis by the corpus luteum.

Clinical Evidence Supporting Triptorelin Use in LPS

A randomized controlled trial published in The Journal of Obstetrics and Gynecology of India in May 2025 evaluated the effects of adding triptorelin to progesterone-based luteal phase support in 150 women undergoing antagonist ICSI cycles. The study compared two groups:

• Study Group : Received 0.1 mg triptorelin on day 6 after OPU + progesterone from the day of oocyte pickup.
• Control Group : Received progesterone only from the day of OPU.

Key Findings:

• The group receiving triptorelin showed significantly higher progesterone levels on day 7 after OPU.
• There was an increase in beta-hCG levels on day 14 post-embryo transfer.
• Implantation rate , clinical pregnancy rate , biochemical pregnancy rate , ongoing pregnancy , and live birth rates were all improved in the triptorelin group compared to the control group (p < 0.05).

These findings support the hypothesis that administering triptorelin during the luteal phase helps restore pituitary function and improves hormonal support for early pregnancy.

Conclusion: Why Triptorelin Matters in ICSI Protocols

Triptorelin is more than just a tool for pituitary suppression during ovarian stimulation. When strategically administered during the luteal phase — particularly in antagonist ICSI cycles — it can significantly improve reproductive outcomes by enhancing luteal function and endometrial receptivity.

Its ability to stimulate the release of LH and FSH six days after oocyte pickup helps maintain adequate progesterone levels, thereby supporting embryo implantation and early pregnancy development.

As research continues to explore optimal dosing and timing, triptorelin remains a promising addition to luteal phase support protocols in modern reproductive medicine.

🔍 References

1. Zahran, K. M., Ahmed, M. M. A., Farghaly, T. A., Elsayed, A. A., & El-Nashar, I. M. (2025). Triptorelin 0.1 mg as a Luteal Phase Support in Antagonist Intracytoplasmic Sperm Injection Cycles . The Journal of Obstetrics and Gynecology of India.
   https://doi.org/10.1007/s13224-025-01895-z

2. Youssef, M. A. F. M., van der Veen, F., Al-Inany, H. G., et al. (2019). Gonadotrophin-releasing hormone agonist versus HCG for oocyte triggering in GnRH antagonist IVF cycles . Cochrane Database of Systematic Reviews, Issue 3.
   https://doi.org/10.1002/14651858.CD008046.pub3

3. Al-Inany, H. G., Abou-Setta, A. M., & Mansour, R. T. (2006). Adding gonadotropin-releasing hormone agonist to progesterone for luteal phase support in intra-cytoplasmic sperm injection cycles: a prospective, randomized, controlled trial . Fertility and Sterility, 85(2), 441–445.
   https://doi.org/10.1016/j.fertnstert.2005.07.1345

4. Orvieto, R. (2017). Is there a place for GnRH-agonist in the luteal phase support of ART cycles? Gynecological Endocrinology, 33(6), 427–430.
   https://doi.org/10.1080/09513590.2017.1296817