Nitrogen vapor shipment of vitrified oocytes: time for caution

Oocyte cryopreservation for fertility preservation, in both medical and elective situations, has significantly increased as freezing technology has improved. Slow freezing techniques demonstrated ∼ 50-80% survival of mature oocytes, however vitrification with ∼ 97% survival has become the preferred method for oocyte cryopreservation around the world. Our work investigated the effect of transporting cryopreserved oocytes to and from a long-term storage facility. Our findings demonstrate that extra caution should be practiced for vitrified oocytes, especially when handling and transferring between shipping and long-term cryopreservation storage containers.