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Pregnancy outcome following fresh vs frozen embryo transfer into gestational carriers using a simplified slow freeze
J H Check1, B Katsoff, C Wilson
1The University of Medicine and Dentistry of New Jersey, Cooper Medical School of Rowan University Cooper Hospital/University Medical Center, Department of Obstetrics and Gynecology Division of Reproductive Endocrinology & Infertility, Camden, NJ, USA. laurie@ccivf.com
Purpose:
To compare pregnancy rates following fresh vs frozen embryo transfer into gestational carriers.
Methods:
Choice of deferring fresh embryo transfer and cryopreserving the embryos vs fresh transfers was not randomized but based on circumstances. The cryopreservation protocol used a simplified slow cool technique avoiding the planar programmable freezer and using a one-step removal of the cryoprotectant.
Results:
The live delivered pregnancy rate was 51.0% (49/96) for fresh embryo transfer vs 34.3% for transfers of frozen thawed embryos in gestational carriers not having a fresh embryo first.
Conclusions:
Using the simplified slow cool cryopreservation protocol with a one-step removal of cryoprotectants pregnancy rates are comparable to what is found in women of similar ages undergoing controlled ovarian hyperstimulation followed by IVF-ET. However, when transferring to a gestational carrier the live delivered pregnancy rates are 50% higher with fresh embryo transfer.
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