Case Report

This case report describes a successful delivery after cryopreservation of a human day-7 blastocyst. A 36-year-old woman, after failed stimulation and cryopreserved-warmed cycles, underwent antagonist-treatment protocol stimulation, and oocytes were recovered transvaginally with ultrasound guidance. Nine mature oocytes were obtained and eight were fertilized by ICSI. A single blastocyst was transferred on day 5, but no implantation occurred. On day 7, one of the non-transferred embryos developed into a blastocyst and was vitrified using a Cryotop procedure. Two months after the previous retrieval cycle, the cryopreserved day-7 blastocyst survived the warming process and was transferred to the patient's uterus. The woman became pregnant and delivered a healthy female.