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Updated: Aug 4, 2026
Cryopreservation of Preimplantation Embryos of Cattle, Sheep, and Goats
Published on: August 5, 2011
Impact of a cryopreservation program on the multiple pregnancy rate associated with assisted reproductive
J A Schnorr1, M J Doviak, S J Muasher
1Department of Obstetrics and Gynecology, The Jones Institute for Reproductive Medicine, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA. schnorja@evms.edu
Objective:
To determine the impact of a cryopreservation program on pregnancy rates and multiple-pregnancy rates in ART cycles.
Design:
Retrospective study.
Setting:
University teaching hospital.
Patient(S):
Women who underwent stimulation for in vitro fertilization at the Jones Institute for Reproductive Medicine between October 1987 and June 1999.
Intervention(S):
Analysis of pregnancy and multiple-pregnancy rates based on the number of embryos transferred.
Main Outcome Measure(S):
Implantation; pregnancy and multiple-pregnancy rates.
Result(S):
Pregnancy rates per transfer increased from 9% when one embryo was transferred to 20% with two embryos, 35% with three embryos, 40% with four embryos, and 41% with five embryos. The rate of twin pregnancies increased to 21% with two embryos, 23% with three embryos, 21% with four embryos, and 22% with five embryos. The triplet pregnancy rates were 8% with three embryos, 9% with four embryos, and 2% with five embryos. A theoretical model limiting the number of embryos transferred to two with cryopreservation and subsequent transfer yields a cumulative pregnancy rate of 77%, a twin rate of less than 20%, and no triplet or higher-order pregnancies.
Conclusion(S):
The use of a cryopreservation program can help maximize pregnancy rates while minimizing multiple-pregnancy rates. Cryopreservation should be considered in all assisted reproductive technology cycles.
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