Live birth from oocytes cryopreserved with slow-freezing protocol and thawed after 6 years of storage.

摘要

After the birth of more than 900 babies from human cryo-preserved oocytes with no apparent increase in congenital anomalies compared to conventional FVF babies [1], oocyte cryopreservation has become a quite widespread technique in Assisted Reproductive Technologies (ART), even in the female fertility preservation programs. Today two procedures are available for oocyte cryopreservation: slow-freezing (SF), the first protocol introduced, and vitrification (VT) [2]. The main goal of VT is to achieve high cryopro-tectant concentration in order to increase the viscosity of the cryoprotectant solution and to suppress ice nucleation [3].