BACKGROUND: The technique of freezing oocytes is still not widely used. Reasons cited for this include the technique's low efficacy and the risk of aneuploidy. However, the introduction of technical changes (the type and concentration of cryoprotective substances; slow freezing and rapid thawing; and fertilization by ICSI) has led to improved results. We present four pregnancies obtained using mature oocytes (in metaphase II) that had been frozen and thawed. The oocytes were donated by young women who were not patients. METHODS: The frozen oocytes (n = 88) came from seven donors aged 18-25 years. The metaphase II oocytes, morphologically normal in appearance, were denuded of their cumulus-corona complex. The cryoprotective freezing solution contained 1,2-propanediol (1.5 mol/l) and sucrose (0.3 mol/l). Freezing was slow and thawing rapid. The oocytes were fertilized by ICSI. RESULTS: Seventy-nine of the 88 thawed oocytes survived (89.8%); 58 were fertilized (73.4% of all those microinjected); and 26 were transferred (44.8% of all those fertilized). Four pregnancies were produced after seven transfers (57.1%). Five children were born from four pregnancies. CONCLUSIONS: With the freezing/thawing technique used, oocyte survival was high ( approximately 90%). The pregnancy rate with frozen oocytes was similar to that obtained using fresh oocytes from donors ( approximately 50%).
BACKGROUND: The technique of freezing oocytes is still not widely used. Reasons cited for this include the technique's low efficacy and the risk of aneuploidy. However, the introduction of technical changes (the type and concentration of cryoprotective substances; slow freezing and rapid thawing; and fertilization by ICSI) has led to improved results. We present four pregnancies obtained using mature oocytes (in metaphase II) that had been frozen and thawed. The oocytes were donated by young women who were not patients. METHODS: The frozen oocytes (n = 88) came from seven donors aged 18-25 years. The metaphase II oocytes, morphologically normal in appearance, were denuded of their cumulus-corona complex. The cryoprotective freezing solution contained 1,2-propanediol (1.5 mol/l) and sucrose (0.3 mol/l). Freezing was slow and thawing rapid. The oocytes were fertilized by ICSI. RESULTS: Seventy-nine of the 88 thawed oocytes survived (89.8%); 58 were fertilized (73.4% of all those microinjected); and 26 were transferred (44.8% of all those fertilized). Four pregnancies were produced after seven transfers (57.1%). Five children were born from four pregnancies. CONCLUSIONS: With the freezing/thawing technique used, oocyte survival was high ( approximately 90%). The pregnancy rate with frozen oocytes was similar to that obtained using fresh oocytes from donors ( approximately 50%).
Authors: Jie Yan; Joao Suzuki; Xiao-Min Yu; Jie Qiao; Frederick W K Kan; Ri-Cheng Chian Journal: J Assist Reprod Genet Date: 2011-05-04 Impact factor: 3.412
Authors: Ho-Joon Lee; Heidi Elmoazzen; Diane Wright; John Biggers; Bo R Rueda; Yun Seok Heo; Mehmet Toner; Thomas L Toth Journal: Reprod Biomed Online Date: 2009-11-27 Impact factor: 3.828
Authors: Jens O M Karlsson; Abdelmoneim I Younis; Anthony W S Chan; Kenneth G Gould; Ali Eroglu Journal: Mol Reprod Dev Date: 2009-04 Impact factor: 2.609
Authors: Min Xu; Erin R West-Farrell; Richard L Stouffer; Lonnie D Shea; Teresa K Woodruff; Mary B Zelinski Journal: Biol Reprod Date: 2009-05-27 Impact factor: 4.285