New Developments in Fertility: Ovarian Cryopreservation

Why was ovarian cryopreservation developed?

Ovarian cryopreservation was born out of a desire to preserve fertility in cancer patients. "Over the last 20 years the issue of fertility in cancer patients has become more important because the rate of cancer survivors has increased dramatically," says Dr. Dror Meirow, IVF specialist of Sheba Medical Center in Tel Aviv, Israel. Treatments such as chemotherapy, radiation, and bone marrow transplants have done wonders by sending certain cancers into remission, but the downside is that these lifesaving regimens may damage—often permanently—organs vital to reproduction. Many patients may even stop menstruating after treatment.

Sentencing a cancer survivor to infertility is devastating, so doctors set about developing ovarian cyropreservation as a way to combat this fate.

How does ovarian cryopreservation work?

Before cancer treatments begin, healthy ovarian tissue is removed from a patient (either an entire ovary or a portion, depending on the unique circumstance of the patient and the preference of the doctor) and cut into sections known as cortical strips.

Cortical strips are healthy ovarian tissue that contains thousands of follicles (or immature eggs). These cortical strips are then frozen. "A special freezing method is used so that ice crystals don't form," says Dr. Meirow.

After a patient finishes her cancer treatment and is given a clean bill of health, she is given two options:

1. A few (not all) of the cortical strips are thawed and then reimplanted in the ovary. Ideally, ovulation resumes normally and the patient continues trying to conceive as she would have before her illness.
2. A few of the cortical strips are thawed; the follicles are matured in the lab, and then eggs are retrieved. The eggs are then fertilized in vitro and the embryo is implanted in the uterus.

Both the tissue removal and the tissue reimplantation process can be done as outpatient procedures. Each procedure should last between 30 and 45 minutes. It typically takes fewer than three days to recover, and then the patient can begin cancer treatment or resume regular activity.