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Updated: Apr 11, 2026
Morphometric Protocol for the Objective Assessment of Blastocyst Behavior During Vitrification and Warming Steps
Published on: February 28, 2019
Frozen blastocyst embryo transfer using a supplemented natural cycle protocol has a similar live birth rate compared
Ruth B Lathi1, Yueh-Yun Chi, Jing Liu
1Department of Obstetrics and Gynecology, Stanford University School of Medicine, Palo Alto, CA, USA, rlathi@stanford.edu.
Purpose:
The purpose of this study is to compare outcomes for a supplemented natural cycle with a programmed cycle protocol for frozen blastocyst transfer.
Methods:
A retrospective analysis was performed of frozen autologous blastocyst transfers, at a single academic fertility center (519 supplemented natural cycles and 106 programmed cycles). Implantation, clinical pregnancy, miscarriage, and live birth and birth weight were compared using Pearson's Chi-squared test, T-test, or Fisher's exact test.
Results:
There was no significant difference between natural and programmed frozen embryo transfers with respect to implantation (21.9 vs. 18.1 %), clinical pregnancy (35.5 vs. 29.2 %), and live birth rates (27.7 vs. 23.6 %). Mean birth weights were also similar between natural and programmed cycles for singletons (3354 vs. 3340 g) and twins (2422 vs. 2294 g)
Conclusion:
Frozen blastocyst embryo transfers using supplemented natural or programmed protocols experience similar success rates. Patient preference should be considered in choosing a protocol.
