Related Experiment Video
Updated: Jun 24, 2026
Protocol for Human Blastoids Modeling Blastocyst Development and Implantation
Published on: August 10, 2022
A predictive model for high-quality blastocyst formation using Day 3 morphological scores in women of advanced
Tingting Zheng1, Ningjing Chen1, Xiaofei Wang1
1Department of Obstetrics and Gynecology, The First College of Clinical Medical Science, Yichang Central People's Hospital, Three Gorges University, 183 Yiling St., Yichang, Hubei, 443003, P.R. China.
Objective:
To develop and validate a simple predictive model based on Day 3 embryo morphology to guide blastocyst culture strategy and optimize transfer outcomes for women of advanced maternal age (AMA).
Methods:
This retrospective study analyzed a total of 6840 cleavage-stage embryos from 1102 fresh oocyte retrieval cycles with subsequent blastocyst culture in AMA patients. Key parameters including the number of oocytes retrieved, Day 2 and Day 3 cell numbers, embryo fragmentation, embryo grade, and the number of high-quality Day 3 embryos were assessed. Their associations with the blastocyst formation rate (BR), high-quality blastocyst formation rate (HBR) and clinical outcomes were evaluated.
Results:
Logistic regression identified the number of high-quality Day 3 embryos as a pivotal independent predictor. A threshold of ≥ 4 high-quality embryos was established. For cycles meeting this criterion, the risk of having no Day 5 transferable blastocyst was 19.30%. Within this group, Day 5 blastocyst transfer was associated with significantly higher clinical pregnancy and live birth rates, a lower multiple pregnancy rate, and improved neonatal outcomes (higher gestational age and birth weight) compared to Day 3 cleavage-stage transfer. The threshold showed good predictive performance in a temporally separated validation cohort (AUC 0.91).
Conclusion:
In AMA patients, a threshold of ≥ 4 high-quality Day 3 embryos may serve as a practical, low-cost criterion to guide blastocyst culture and elective single blastocyst transfer. The approach is associated with favorable clinical and neonatal outcomes but requires prospective validation in unselected populations.
