Cryopreservation of Sperm, Oocyte or Embryo

Cryopreservation—the ability to freeze and thaw with retention of viability—provides flexibility in human infertility therapy when gametes or embryos are handled in vitro because frozen tissue can be stored indefinitely in liquid nitrogen at -196°C.

partner or donor sperm be frozen for therapeutic insemination (TI) at a subsequent date, but sperm banking provides the assisted reproductive technologies (ART) coupled with a backup option if a sample cannot be collected on demand or if sample quality is poor on the day eggs are available. In the case of donor insemination, samples are quarantined for 6 months before use, thereby minimizing the risk of infectious disease transmission.

There are a growing number of indications for oocyte cryopreservation as oocyte donation, fertility preservation for cancer patients or social egg freezing. The reproductive behaviour of women has been changed in the last few years. There is a delay in the age of motherhood due to various reasons like career, lifestyle or education. It is known, that in women older than 35 years, a reduction of ovarian reserve is observed. The use of younger cryopreserved oocytes can reduce the risk of foetal loss and aneuploidies associated with ageing oocytes. Oocyte cryopreservation simplifies the logistics of assisted reproductive technology (ART)cycles in donation programme, and there is no need for menstrual cycle synchronization between donor and recipient.

Cryopreservation of human embryos is a safe procedure, which has been carried out for more than the last 30 years. In the development of in vitro techniques and together with single embryo transfer becoming greater demand for an efficient and reliable cryopreservation method for surplus embryos. It is possible to cryopreserve the human zygotes immediately after fertilization, at the pronuclear stage or embryos during early cleavage stages (2–8 cells) or at the expanded blastocyst stage (after 5–7 days in culture).