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Volume 16, No 2 February 2008
Oocyte zona birefringence intensity is associated with embryonic implantation potential in ICSI cycles
M Montag1,4, T Schimming2, M Köster1, C Zhou3, C Dorn1, B Rösing1, H van der Ven1, K van der Ven1 1 Department of Gynecological Endocrinology and Reproductive Medicine, University of Bonn, 53127 Bonn, Germany 2OCTAX Microscience GmbH, Hohe Str 700-5a, 35745 Herborn, Germany 3Reprod. Medical Centre, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510080 China 4Correspondence: Tel: 49 228 287 15449; Fax: 49 228 287 14651; e-mail: Markus.Montag@ukb.uni-bonn.de
A retrospective study recently showed that oocytes presenting with a high birefringence of the inner zona layer were more often associated with conception cycles. To further investigate these findings, a prospective study was conducted between September 2005 and September 2006 including intracytoplasmic sperm injection (ICSI) cycles presenting with at least two embryos for transfer. Using a polarization imaging system, oocytes were classified prior to ICSI treatment as having either a high zona birefringence (HZB) or a low zona birefringence (LZB) of the zona pellucida. Using zona birefringence as the only selection criterion, two fertilized oocytes, preferably derived from HZB oocytes, were selected for further culture and transfer. The required criteria were met by 135 ICSI cycles (124 patients; 34.9 ± 4.1 years of age). Embryos for transfer were used in 20 cycles derived from HZB/HZB oocytes, in 50 cycles from HZB/LZB oocytes and in 65 from LZB/LZB oocytes. The corresponding implantation (P < 0.025), pregnancy (P < 0.005) and live birth (P < 0.005) rates were significantly different between HZB/HZB and HZB/LZB versus LZB/LZB group. Embryo development was superior in embryos derived from HZB oocytes. This study concludes that oocyte zona birefringence is a good selection criterion and a good predictive criterion for embryo implantation potential.
Reproductive BioMedicine Online 2007 http://www.rbmonline.com/Article/3161 [e-pub ahead of print on 27 November 2007]
Reproductive BioMedicine Online 2008 Vol. 16 No.2. 239–244
Keywords: human oocyte, ICSI, implantation, polarization microscopy, zona pellucida
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