Conference Coverage

Ovarian cryopreservation should no longer be experimental



– Ovarian tissue cryopreservation should no longer be considered experimental, Sherman J. Silber, MD, said at the annual meeting of the American Society for Reproductive Medicine.

That claim is based on more than 20 years of experience at his center performing the procedure and results he presented from patients for whom frozen ovarian tissue has been reimplanted resulting in a spontaneous pregnancy.

“For prepubertal girls with cancer and for patients who have already had a preliminary round of chemotherapy, ovarian tissue freezing is the only method available to preserve their fertility,” said Dr. Silber, of the Infertility Center of St. Louis in Chesterfield, Missouri. “It is also the only method available to preserve their fertility.”

“I have very strong feelings about this,” he added. “It has huge societal implications for insurance payments.”

Dr. Silber presented results of ovarian tissue freezing and reimplantation at his center beginning in 1997, where 115 patients between the ages of 2 and 35 years underwent the procedure using the same technique. Of these patients, 14 women came back years later to have their frozen ovary cortex reimplanted. Dr. Silber and his group followed these patients monthly for more than 2 years after reimplantation for signs of return of menses, hormonal changes, pregnancy, and live birth.

Most of the patients who chose ovarian tissue freezing had cancer. Eight patients underwent the procedure after being diagnosed with solid tissue cancer and three had leukemia, while two patients underwent ovarian tissue freezing due to premature ovarian failure, and one because of multiple sclerosis. Patients who underwent reimplantation were menopausal for at least 3 years, said Dr. Silber.

Dr. Silber also described the technique used for reimplantation. After the cortical tissue was thawed, the tissue was quilted into one piece from three to five slices using 9-0 nylon interrupted sutures. The quilted tissue was then sutured to the medulla after the surgeon completely removed the dead cortex from the other ovary. “Hemostasis was achieved with micro bipolar forceps,” said Dr. Silber. “Constant irrigation was employed with pulsed heparinized media because we wanted to avoid adhesions, and we wanted to try for spontaneous pregnancy rather than IVF.”

“Then, we put [the quilted ovarian slices] on to the medulla on the other side in such a way that the fallopian tube would be able to reach and catch any egg that’s ovulated during that time,” he added.

Dr. Silber and his group found that, over time, follicle-stimulating hormone (FSH) levels sharply decreased to normal or near-normal levels between 69 days and 133 days after the procedure while Anti-Müllerian hormone (AMH) levels dramatically rose to higher levels between 133 days and 227 days post-procedure before dropping to very low levels, “and the AMH remained at low levels despite the fact that [transplants] would last 8 to 10 years,” said Dr. Silber.

Of the 14 cases where frozen ovarian tissue was reimplanted, 11 patients (78%) achieved pregnancy, 10 patients (71%) delivered healthy babies, and 1 patient (9%) experienced a miscarriage. All patients had spontaneous pregnancies, and none used in vitro fertilization (IVF), noted Dr. Silber. There were 2 patients who had four children from transplanted ovarian tissue, and 2 of 3 patients with leukemia had a total of five children.

Additionally, Dr. Silber’s group examined the literature for other examples of ovarian tissue reimplantation after cryopreservation to determine how many live births resulted from the procedure. They found an additional 170 live births in addition to the 15 live births at their center, with a pregnancy rate ranging from 31% to 71% in different studies. Cancer was not transmitted from mother to child in any case, said Dr. Silber.

Compared with egg freezing, there is a benefit to performing ovarian tissue freezing, even after chemotherapy has begun, noted Dr. Silber. The cost of ovarian tissue freezing is also roughly one-tenth that of egg freezing, and the procedure is less burdensome than multiple cycles with the potential for ovarian hyperstimulation, and it restores the hormone function and the fertility of eggs after reimplantation.

“Because the greater primordial follicle recruitment decreases as the ovarian reserve decreases, you can put a piece of ovary tissue back every 8 years, and a woman can have endocrine function until she’s 100 years old,” said Dr. Silber.

Dr. Silber reported no relevant conflicts of interest.

SOURCE: Silber SJ. ASRM 2019. Abstract O-203.

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