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Updated: May 1, 2026
Cryopreservation of Preimplantation Embryos of Cattle, Sheep, and Goats
Published on: August 5, 2011
Ectopic pregnancy rates after frozen versus fresh embryo transfer: a meta-analysis
Byung Chul Jee1, Chang Suk Suh, Seok Hyun Kim
1Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, South Korea.
Background/Aims:
The aim of this meta-analysis was to determine whether frozen embryo transfer (ET) increases ectopic pregnancy (EP) rate compared with fresh ET.
Methods:
A meta-analysis was performed of data from seven comparative studies including 13,059 pregnancies that resulted from nondonor in vitro fertilization cycles.
Results:
The EP rate was 2.31% (49/2,125 pregnancies) for frozen ET and 1.48% (162/10,934 pregnancies) for fresh ET. These rates were statistically not different when assessed either by random (OR 1.66, 95% CI 0.62-4.41) or fixed effect model (OR 1.17, 95% CI 0.84-1.63).
Conclusions:
The combined data presented in this meta-analysis do not support an increased risk of EP following frozen ET compared with fresh ET. However, as there was a substantial heterogeneity among the studies analyzed, the authors consider that further well-designed studies controlling for several potential biases which could affect the EP risk should be conducted.
