Ideal lag time from ovulation to oocyte aspiration using a GnRH agonist trigger

Area of Science:

• Reproductive Endocrinology
• Assisted Reproductive Technology (ART)

Background:

• Oocyte maturation and ovulation in ART require hormonal stimulation and adequate "lag time" between trigger and aspiration.
• Insufficient lag time leads to suboptimal oocyte yield, while excessive duration risks spontaneous ovulation.

Purpose of the Study:

• To determine the optimal "lag time" for oocyte aspiration in women undergoing intracytoplasmic sperm injection (ICSI) using a gonadotropin-releasing hormone (GnRH) antagonist protocol with a GnRH agonist trigger.
• To investigate the correlation between "lag time" and key ART outcomes.

Main Methods:

• Retrospective analysis of 220 women undergoing ICSI with a GnRH antagonist protocol and GnRH agonist trigger (02/2012-03/2018).
• Patients were stratified into four groups based on "lag time": 34.00-34.99h, 35.00-35.99h, 36.00-36.99h, and ≥37.00h.
• Statistical analyses included Kruskal-Wallis test, Chi-Square, and Spearman's rho correlation.

Main Results:

• A significant positive correlation was observed between "lag time" and the total number of oocytes retrieved (ρ = 0.174, p = 0.01) and mature M2 oocytes retrieved (ρ = 0.138, p = 0.04).
• The 36.00-36.99h "lag time" group yielded significantly more M2 oocytes compared to the 35.00-35.99h group (12.4 ± 7.1 vs 9.4 ± 6.2; p = 0.039).
• Live birth rates per fresh embryo transfer differed significantly across the four "lag time" groups (χ² = 9.364, p = 0.025).

Conclusions:

• Optimal "lag time" in GnRH antagonist protocols with GnRH agonist trigger is crucial for maximizing M2 oocyte yield.
• Extending "lag time" to approximately 36 hours appears to enhance oocyte retrieval and potentially improve live birth rates in ICSI cycles.
• Further research is warranted to refine "lag time" recommendations for personalized ART protocols.