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The Scientific World Journal
Volume 2012 (2012), Article ID 785421, 4 pages
Research Article

Freezing of Oocytes and Its Effect on the Displacement of the Meiotic Spindle: Short Communication

1Infertility and IVF Center of Buda, Szent Janos Hospital, Budapest 1125, Hungary
2Faculty of Veterinary Science, Szent István University, István u. 2, Budapest 1078, Hungary
3Subsidized Research Unit, Hungarian Academy of Sciences, 1525 Budapest, Hungary

Received 27 October 2011; Accepted 4 December 2011

Academic Editors: C. Matas and J. B. A. Oliveira

Copyright © 2012 János Konc et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Our investigations focused on spindle dynamics/displacement in frozen-thawed human oocytes. In each oocyte, prior to freezing and after thawing and culturing, the presence/location of the spindle was determined with the Polscope technique. A total of 259 oocytes have been thawed with a survival rate of 81.1%. From the 210 survived oocytes, 165 were fertilized (78.6%) and 89.1% of them cleaved. A total of 143 embryos were transferred into 63 patients resulting in 11 clinical pregnancies (17.5%), 7 of which resulted in live birth of 8 babies (1 twin pregnancy). We were able to detect the spindle in 221 of 259 oocytes (85.3%). After thawing and culturing the oocytes, we were able to visualize the spindle in 177 of 210 oocytes (84.3%). In 83 of these 177 oocytes, the spindle was observed to be in the same location as it was before cryopreservation (46.9%). However, in 94 of these 177 oocytes (53.1%), the spindle reformed in a different position/location relative to the polar body. Our results show that after thawing and culture in half of the spindle-positive oocytes the spindle was detected in a new location, indicating that the spindle and the polar body move relative to each other.