GnRH-agonist triggering for final oocyte maturation in GnRH-antagonist IVF cycles induces decreased LH pulse rate and amplitude in early luteal phase: a possible luteolysis mechanism

Abstract

The use of GnRH agonist to trigger final oocyte maturation in GnRH-antagonist in vitro fertilization (IVF) cycles has been shown to significantly reduce or even eliminate the risk of ovarian hyperstimulation syndrome (OHSS) by inducing rapid luteolysis early in the luteal phase. The exact mechanism of this early luteolysis is still widely unknown. Since luteinizing hormone (LH) has a major role in corpus luteum support, we sought to explore the pattern of LH secretion early in the luteal phase. Ten high risk patients for developing OHSS and triggered with GnRH agonist were included. Frequent blood sampling (every 20 min for 6 h) to measure LH, estradiol and progesterone was done on the day of oocyte collection (n = 5, Group 1) and on the day of embryo transfer, 48 h after oocyte collection (n = 5, Group 2). We found that the mean LH concentration and its secretion rate decreased significantly in Group 2 compared to Group 1. Both groups had similar number of LH pulses characterized by very small amplitude. In Group 2, there was a steady significant decrease in estradiol and progesterone over time. The results of this study show that LH secretion deviates significantly from normal physiologic pattern, which can explain, at least in part, the post-GnRH-agonist trigger early luteolysis mechanism.

Chinese abstract

已证明在体外受精（IVF）GnRH拮抗剂周期中, 用GnRH激动剂触发卵泡最终成熟可以通过在黄体早期引起快速黄体溶解而显著降低或甚至消除卵巢过度刺激综合征（OHSS）风险。这种早期黄体溶解的确切机制还普遍未知。由于促黄体激素（LH）在黄体支持中起主要作用, 我们试图探索黄体早期LH的分泌模式。纳入10名具有OHSS高风险的患者, 用GnRH激动剂触发卵泡最终成熟。在收集卵泡(n = 5, 组1)和胚胎移植的当天以及收集卵泡48h后 (n = 5, 组2)频繁取血标本（6h内每20min取一次）, 检测LH、雌二醇和孕酮。我们发现, 与组1相比, 组2的平均LH浓度和它的分泌速度 显著降低了。两组具有相似数量和非常小幅度特征的LH脉冲。在组2中, 雌二醇和孕酮随着时间的推移有稳定的显著降低。结果表明, 本研究中的LH分泌与正常生理模式有显著偏差。此结果至少可部分解释GnRH激动剂触发后早期黄体溶解的机制。

Keywords:

• GnRH agonist
• GnRH antagonist
• luteolysis
• ovarian stimulation
• ovulation triggering

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.