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Updated: Jun 3, 2026
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Published on: March 2, 2017
Frozen-thawed blastocyst transfer reduces ectopic pregnancy risk: an analysis of single embryo transfer cycles in
Osamu Ishihara1, Akira Kuwahara, Hidekazu Saitoh
1Department of Obstetrics and Gynecology, Faculty of Medicine, Saitama Medical University, Saitama, Japan. osamishr@saitama-med.ac.jp
Objective:
To evaluate the effect of frozen-thawed blastocyst transfer on ectopic pregnancy (EP) rate.
Design:
Retrospective analysis.
Setting:
Japanese registry of assisted reproductive medicine.
Patient(S):
Women who were registered during 2008.
Intervention(S):
None.
Main Outcome Measure(S):
Rates of live birth, EP, and spontaneous abortion in single blastocyst and cleavage-stage ET cycles in both fresh and frozen-thawed were determined.
Result(S):
In the frozen-thawed single blastocyst transfer cycles, 84 EPs of 10,312 clinical pregnancies (0.81%) were reported. There were 25 EPs of 1,361 clinical pregnancies (1.8%) in fresh IVF single blastocyst transfer cycles and 19 of 1,352 (1.4%) in fresh intracytoplasmic sperm injection single blastocyst transfer cycles. The rate of EPs after frozen-thawed single blastocyst transfers varied between 0.56% and 0.97% after stratification by age group.
Conclusion(S):
Frozen-thawed blastocyst transfers have reduced EP rates significantly compared with fresh blastocyst transfers.
