Ovarian cryopreservation could delay menopause indefinitely

Ovarian tissue cryopreservation has been successfully used to maintain fertility in women undergoing treatment for cancer and other chronic illnesses. A new study led by Yale School of Medicine researchers finds if used in healthy women, the procedure could delay menopause by decades.

“For the first time in medical history, we have the ability to potentially delay or eliminate menopause,” says Kutluk Oktay, MD, PhD, adjunct professor at Yale School of Medicine and senior author who led the study. In 1999, Oktay developed and performed the world's first ovarian transplant procedure with cryopreserved tissue for a patient with medical indications. 

The outpatient surgical procedure laparoscopically removes layers of the outer portion of the ovary, which contains hundreds of thousands of dormant, immature eggs. These eggs are specially frozen, then thawed and transplanted back into the patient's body, typically years later.

Oktay and his team worked on building a model, published in the American Journal of Obstetrics and Gynecology, to predict how long the surgery could potentially delay menopause in healthy women under a range of circumstances. The study found that the age at which a woman gets the procedure plays a major role in how long menopause can be delayed. “The younger the person at the age of ovarian tissue freezing, the larger numberr of eggs she has, and as a result the longer the delay in menopause,” Oktay says. 

The model also accounted for the amount of ovarian tissue collected, the survival rate of the eggs in the harvested ovarian tissue after the transplantation, and the number of procedures the transplant is broken up into. 

The team's model shows freezing ovarian tissue by age 40 and having it transplanted back right before menopause will significantly delay menopause in most women. The study also found that if the procedure is performed before the age of 30, with an egg survival rate of 80 percent or more after the transplantation, it could delay menopause by up to 50 years or more. "That's exceeding the average lifespan," says Oktay. "So hypothetically, there are case scenarios where women may not have to experience menopause."

The study generated an online calculator tool that patients and doctors can access to estimate the length of delay one can expect based on the key factors the study has identified. 

While the procedure can also preserve and delay natural fertility, "it is not aimed at preserving fertility to ages not medically deemed safe by the American College of Obstetricians and Gynecologists, or the guidelines of the American Society of Reproductive Medicine for donor egg recipients," Oktay says. However, researchers say delaying menopause could carry its own health benefits.

Prior studies have shown women who naturally experience later menopause have a lower risk of Alzheimer's disease, depression, and cardiovascular disease. "The preliminary evidence suggests that, based on women who naturally experience late menopause, the benefits of a delay of about 10 years to about age 60 outweigh the risks," Oktay says.

The team says more work is needed to define the potential benefits of delaying menopause through ovarian cryopreservation.

Oktay's team includes ovarian biologist Joshua Johnson, PhD of the University of Colorado in Denver, mathematician Sean Lawley, PhD, of the University of Utah, and bioinformatics expert John Emerson, PhD, of Yale.