Oocyte Cryopreservation Comparing Fresh and Vitrified Sibling Oocytes

Vitrification is a method to cryopreserve biological specimens that are sensitive to chilling injury such as oocytes and embryos, and it has been employed with increased survival rate and live births (Hong et al., 1999; Kuleshova et al., 1999; Yoon et al., 2000; Chung et al 2000; Wu et al., 2001: Kuwayama et al 2006). In their study the researchers propose to directly compare oocyte survival, fertilizaton and embryo development between sibling oocytes. The Cryotop method of vitrification, which the researchers aim to investigate in their study, has been reported as the most efficient method for human oocytes cryopreservation (Kuwayama et al, 2005, Antinori et al, 2006, Lucena et al, 2006, Cobo et al, 2008). Follow up of over 200 infants conceived from vitrified oocytes (Chian et al, 2008) indicate that the mean birth weight and the incidence of congenital anomalies are comparable to that of spontaneous conceptions in fertile women or infertile women undergoing IVF treatment.