Cryopreservation

Cryopreservation is freezing tissue or cells in order to preserve it for the future.

Cryopreservation is used in infertility programs to freeze and store sperm, eggs or to freeze “leftover” embryos from an in vitro fertilization cycle. It is an effective method of freezing sperms or eggs in a patient about to undergo chemotherapy. During puberty (usually around age 13 to 14), a boy’s testicles start making sperm, and they normally will keep doing so for the rest of his life. Chemotherapy (chemo) works by killing cells in the body that are dividing quickly. Since sperm cells divide quickly, they are an easy target for damage by chemo. Permanent infertility can result if all the spermatogonial stem cells (the immature cells in the testicles that divide to make new sperm) are damaged to the point that they can no longer produce maturing sperm cells. So, it is always advisable to preserve sperm prior to chemo/radiotherapy. Similarly cancer treatment can affect ovaries in female patients and completely deplete all the ovarian reserve, rendering ovaries non-functional. Hence, cancer patients who still have to start their families should be counseled about freezing their eggs prior to cancer treatment.

There are 2 methods currently used for freezing in IVF labs.

  • Slow freezing
  • Vitrification (ultra-rapid freezing)

Our IVF program has been using vitrification to freeze sperm, oocytes and embryos.