Live birth from a frozen–thawed pronuclear stage embryo almost 20 years after its cryopreservation

Objective To report a live birth after transfer of cryopreserved pronuclear embryos in cryostorage for almost 20 years. Design Case report. Setting Academic IVF center. Patient(s) A 42-year-old female patient with low ovarian reserve receiving donated embryos. These embryos were the result of an anonymous donation from an infertile couple who had conceived during her IVF treatment. Intervention(s) Cryopreservation (slow-freeze method) and thawing of pronuclear stage embryos, and ultrasound-guided uterine ET. Main Outcome Measure(s) Live birth. Result(s) Five pronuclear embryos were thawed; two embryos survived, cleaved, and were transferred on day 2. A singleton term pregnancy was achieved with the delivery of a healthy boy. Conclusion(s) A healthy live birth was documented after uterine transfer of pronuclear stage cryopreserved (slow freeze)–thawed embryos that were in storage for 19 years and 7 months. To our knowledge this case represents the “oldest” cryopreserved human embryos resulting in a live birth to date.