Penn Fertility Care

Egg Freezing

What is Cryopreservation?

Cryopreservation is a precise method used to preserve embryos, eggs, ovarian tissue, and sperm by cooling and storing them at a very low temperature and then thawing them at a future date for use.

Through egg freezing, specialists can preserve a female cancer patient’s eggs until cancer treatment is completed or enable women to postpone having children — either because they do not currently have a partner, or for other personal or medical reasons. Later, when a woman is ready to become pregnant, the eggs can be thawed, fertilized, and the embryo can then be transferred to the uterus.

The egg retrieval process for oocyte cryopreservation is the same as that for in vitro fertilization.

  • The ovaries are stimulated through hormone injections to produce multiple egg-containing follicles.
  • Progression of follicular development is followed by evaluating hormone levels and performing ultrasounds at the appropriate times.
  • A transvaginal ultrasound guides the retrieval of the eggs and the eggs are immediately frozen.