IMR Press / CEOG / Volume 36 / Issue 1 / pii/1630635157811-1765686091

Clinical and Experimental Obstetrics & Gynecology (CEOG) is published by IMR Press from Volume 47 Issue 1 (2020). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with S.O.G.

Editorial
Advances in oocyte cryopreservation - Part II: rapid cooling using vitrification
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1 The University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School at Camden, Cooper Hospital/University Medical Center, Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology & Infertility, Camden, NJ (USA)
Clin. Exp. Obstet. Gynecol. 2009, 36(1), 5–9;
Published: 10 March 2009
Abstract

Purpose: The need for freezing oocytes has been established for females undergoing potential therapy that could damage their ovarian egg reserve, for ethical or religious reasons (not having excess embryos frozen) or for women nearing the age of lower fecundity but not married and not ready to use donor sperm. Applying cryopreservation techniques for oocytes used for embryos resulted in very poor pregnancy results. A rapid flash freezing technique has rekindled interest in oocyte freezing known as vitrification. Methods: Certain modifications, especially minimizing the volume, have resulted in marked improved pregnancy rates with vitrified thawed oocytes. The lower volume allows decreased exposure to the toxic cryoprotection. Commercial interests have developed an effective device called cryotop but some concerns about microorganism contamination exist because it is an open system. Modifications have been made to make available the cryotip, a closed device which addresses the contamination issue. Results: Frozen oocyte survival rates upon thawing fertilization rates and subsequent pregnancy rates after embryo transfer have been reported comparable to data with frozen thawed embryos. Conclusions: Because of the uncertainty of the programmable freezer used for the slow cool method and because there has been more commercial interest in the vitrification method, the “flash” freeze protocol seems to have an edge over the slow cool method for oocyte freezing.
Keywords
Cryopreservation
Oocytes
Vitrification
Slow cooling
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