Related Experiment Video
Updated: May 22, 2026

08:46
Fertility Preservation Through Oocyte Vitrification: Clinical and Laboratory Perspectives
Published on: September 16, 2021
Revisiting the Trigger-to-Oocyte Retrieval Interval: A Machine Learning-Guided Strategy for Improving Oocyte Yield in
Yoko Suzuki1,2, Ying Liu2, Michihiro Tanikawa1
1Department of Obstetrics and Gynecology, Graduate School of Medicine The University of Tokyo Tokyo Japan.
Reproductive Medicine and Biology
|May 21, 2026
Summary
Extending the trigger-to-oocyte retrieval interval (TOI) improves mature oocyte rate and oocyte retrieval rate in women with diminished ovarian reserve. Machine learning models can optimize TOI for better IVF outcomes.
Area of Science:
- Reproductive Medicine
- In Vitro Fertilization (IVF)
- Ovarian Reserve
Background:
- Standard IVF protocols use a trigger-to-oocyte retrieval interval (TOI) of 34-36 hours to prevent premature ovulation.
- Women with diminished ovarian reserve (DOR) or advanced age often experience premature ovulation or empty follicles with standard TOI.
- Nonsteroidal anti-inflammatory drugs (NSAIDs) can prolong the ovulatory window, suggesting potential for TOI extension.
Purpose of the Study:
- To evaluate the impact of extending the TOI (≥36 hours) on mature oocyte rate (MOR) and oocyte retrieval rate (ORR).
- To develop and validate machine learning models for predicting oocyte yield and optimizing individualized TOI in IVF.
- To investigate TOI optimization strategies for patients with diminished ovarian reserve (DOR).
Main Methods:
- Retrospective analysis of 15,033 IVF cycles to assess the effects of extended TOI (≥36 hours) on MOR and ORR.
- Training seven machine learning models to predict mature oocytes (MII) and retrieved oocytes (Oocount).
- External validation of the best-performing model on 387 unseen cases to assess predictive accuracy for MOR and ORR.
Main Results:
- Extended TOI significantly improved MOR (p=0.00034) and ORR (p=0.0051) in POSEIDON groups 3 and 4, particularly benefiting DOR patients.
- The Extreme Gradient Boosting (XGBoost) model demonstrated the highest predictive accuracy for MII and Oocount.
- External validation showed a decrease in R-squared but maintained acceptable MAE and RMSE, indicating model reliability.
Conclusions:
- Extending the TOI is a viable strategy to enhance both MOR and ORR in patients with DOR.
- Machine learning models can accurately predict oocyte yield, enabling calculation of MOR and ORR across various TOIs.
- Individualized TOI optimization using predictive models facilitates improved IVF outcomes and retrieval timing.

