Fertility Preservation: Comparing Egg Freezing and Ovarian Tissue Freezing

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Women consider fertility preservation for both personal and medical reasons. An article published in the New England Journal of Medicine compares egg freezing and ovarian tissue freezing techniques.

Why Consider Elective Fertility Preservation?

Today, some women are considering fertility preservation because they are delaying starting a family and worry that they might have trouble conceiving when they decide the time is right. However, fertility preservation is most commonly recommended for women diagnosed with serious illnesses so that they can store their eggs before undergoing treatment. These include:

  • Women who have been advised to have a part, or all, of their reproductive system surgically removed due to ovarian, cervical, or uterine cancer or severe endometriosis.
  • Women diagnosed with other forms of cancer since the chemotherapy and radiation used to treat cancer can reduce fertility or cause sterility.
  • Women with medical conditions such as lupus or rheumatoid arthritis since the medications prescribed can damage or destroy ovarian function.
  • Women with a family history of early menopause.
  • Women undergoing in vitro fertilization and who, for religious or ethical reasons regarding what to do with unused eggs, choose not to freeze an embryo.

Regardless of the reasons, fertility preservation is a viable option for many women and couples. An article published in the New England Journal of Medicine compares two options for elective fertility preservation – egg freezing and ovarian tissue freezing.

Cryopreservation: Egg Freezing

The egg extraction process begins with blood tests and ultrasounds to help doctors determine if a woman is a good candidate for egg freezing. If she is, she will be prescribed medication to increase the levels of hormones naturally created by the body to stimulate the ovaries and ripen multiple eggs. The eggs are then retrieved and frozen using either a slow- or flash-freeze process. Later on, these eggs can be thawed, fertilized, and implanted into the woman’s uterus. Previous research indicates that egg freezing is not associated with an increased risk of birth defects.

Cryopreservation: Ovarian Tissue Freezing

In this procedure, a portion of ovarian tissue with egg follicles is removed and frozen. In cases where there is a risk of transplanting back tissue that could turn cancerous, individual follicles are harvested. When the woman is ready to become pregnant, the tissue is then put back into the body. In 95% of cases, the ovarian tissue is able to produce eggs for four to five years, although this can be longer. As with egg freezing, this technique has been shown to be safe. However, a major advantage of this method is that it allows for spontaneous pregnancy.

Advances in reproductive medicine mean that women now have several options when considering fertility preservation. The authors of this review recommend that women considering delaying pregnancy or women diagnosed with certain illnesses speak with their healthcare providers early in order to plan for their future reproductive health.

Written by Debra A. Kellen, PhD

Review Citation: Fertility Preservation in Women. N. Engl. J. Med 2017 Oct 26;377(17)1657-1665, J Donnez, MM Dolmans   DOI: 10.1056/NEJMra1614676