Oocyte maturation and pregnancy outcomes in relation to gonadotropin duration in antagonist cycles.
Gn stimulation duration significantly affects oocyte maturation, with an optimal window of 8-10 days linked to better pregnancy outcomes.
Where it sits
this study against the rest of the buserelin corpusSummary and findings
This study evaluated the association between gonadotropin (Gn) stimulation duration and oocyte maturation and pregnancy outcomes in 9372 GnRH antagonist cycles. The analysis found that Gn duration had a significant nonlinear association with oocyte maturation, with an optimal duration of 8-10 days linked to higher pregnancy likelihood. No therapeutic claims are made.
Abstract
<h4>Objective</h4>Gonadotropin (Gn) stimulation duration is a modifiable factor in antagonist protocols, yet its association with oocyte maturation and pregnancy outcomes remains unclear. This study aimed to determine whether Gn duration is independently associated with oocyte maturation and pregnancy outcomes after controlling for key confounders and to identify an optimal Gn window in GnRH antagonist cycles with fresh embryo transfer.<h4>Methods</h4>This retrospective study included 9372 GnRH antagonist cycles at Xiangya Hospital. Multivariable regression models adjusting for confounders were used to assess the associations of Gn duration with oocyte maturation and pregnancy outcomes. Subgroup analyses were stratified by ovarian response. Generalized additive models were employed to identify nonlinear trends, followed by segmented and LOESS regression to determine the optimal duration.<h4>Results</h4>After comprehensive adjustment, Gn duration maintained a significant nonlinear association with oocyte maturation (adjusted OR 1.07, 95% CI 1.05-1.09, <i>p</i> < .001), plateauing at approximately 9 days. Each additional stimulation day before 9 days was associated with increased maturation odds (adjusted OR 1.11, 95% CI 1.06-1.17; <i>p</i> < .001), while extended duration beyond 9 days showed no significant benefit (adjusted OR 0.94, 95% CI 0.88-1.01; <i>p</i> = .08). This association was absent in very low responders (≤5 oocytes) but consistent across other response subgroups. The 8-10 day duration window was associated with the highest likelihood of pregnancy and live birth.<h4>Conclusion</h4>In GnRH antagonist cycles, Gn duration is associated with oocyte maturation and pregnancy outcomes following fresh embryo transfer, even after adjusting for key confounders. The 8-10 day Gn window represents a range associated with the highest likelihood of clinical pregnancy and live birth. These findings support prioritizing dynamic, response-adapted stimulation protocols aimed at achieving trigger criteria within this window, rather than adhering to fixed duration targets.
Background
This paper addresses the relationship between gonadotropin stimulation duration and its effects on oocyte maturation and pregnancy outcomes in GnRH antagonist cycles. Previous studies have suggested that Gn duration may influence these outcomes, but the optimal duration remains unclear. Understanding this relationship is crucial for optimizing fertility treatment protocols.
Methods
The study utilized a retrospective design, analyzing 9372 GnRH antagonist cycles from Xiangya Hospital. Multivariable regression models were employed to control for confounders, and generalized additive models were used to assess nonlinear associations. The primary outcomes included oocyte maturation rates and pregnancy outcomes following fresh embryo transfer.
Results
The primary endpoint indicated that Gn duration had a significant nonlinear association with oocyte maturation, with an adjusted OR of 1.07 (95% CI 1.05-1.09, p<0.001). Each additional day of stimulation before 9 days increased maturation odds (adjusted OR 1.11, 95% CI 1.06-1.17; p<0.001), while extending beyond 9 days showed no significant benefit (adjusted OR 0.94, 95% CI 0.88-1.01; p=0.08).
Interpretation
These findings suggest that while there is a statistically significant association between Gn duration and oocyte maturation, the clinical significance of extending Gn beyond 9 days is questionable. The absence of association in very low responders and the reliance on a single-site retrospective design may limit the generalizability of the results. This study adds to the existing literature by identifying an optimal duration window for Gn stimulation.
Key findings
- Adjusted OR 1.07 for oocyte maturation per day of Gn stimulation, 95% CI 1.05-1.09, p<0.001.
- Each additional stimulation day before 9 days increased maturation odds (adjusted OR 1.11, 95% CI 1.06-1.17; p<0.001).
- Extended duration beyond 9 days showed no significant benefit (adjusted OR 0.94, 95% CI 0.88-1.01; p=0.08).
- The 8-10 day Gn duration window was associated with the highest likelihood of pregnancy and live birth.
- Association absent in very low responders (≤5 oocytes).
Limitations
- Retrospective study design.
- Single-site analysis.
- Potential residual confounding despite adjustments.
- No data on long-term outcomes.