Embryo cryopreservation is a routine practice within advanced reproductive technology (ART) clinics. During a frozen embryo transfer cycle, the uterus is prepared with both estrogen and progesterone hormones to make the uterus receptive. This hormonal preparation typically takes 3-4 weeks of time. During this 3–4-week time period, hormone levels and the uterine lining are monitored to ensure optimal uterine receptivity. Cryopreserved embryos are then thawed and transferred back into the uterus. Approximately 95% of day 5-6 blastocysts typically survive the freeze-thaw process. Pregnancy testing typically occurs 10-14 days after the embryo transfer. If high quality, chromosomally normal embryo(s) are transferred, approximately 65% clinical pregnancy rate is achieved per frozen embryo transfer. Embryo cryopreservation techniques and capabilities have become an increasingly important therapeutic strategy in assisted reproduction.
