In what doctors call a breakthrough, a cancer patient in France gave birth to the first baby conceived from an immature egg that was matured in the laboratory, frozen, then later thawed and fertilized.
"We were delighted that the patient became pregnant without any difficulty and successfully delivered a healthy baby at term," said team leader Michaël Grynberg, head of reproductive medicine and fertility preservation at Antoine Béclère University Hospital, near Paris.
Loss of fertility is always a potential hazard after chemotherapy and radiation treatments for younger female cancer patients. In such cases, doctors typically induce "ovarian stimulation" to produce and harvest mature eggs from ovaries so that they can be frozen for potential future use.
"However, for some patients, ovarian stimulation isn't feasible due to the need for urgent cancer treatment or some other contraindication," Grynberg said in a news release from the journal Annals of Oncology, which published the report Feb. 19.
The French team hoped that in these cases, a technique called in vitro maturation (IVM), where the egg maturation process is induced in the laboratory, might work.
"My team and I trusted that IVM could work when ovarian stimulation was not feasible," Grynberg said. "Therefore, we have accumulated lots of eggs that have been vitrified [frozen] following IVM for cancer patients and we expected to be the first team to achieve a live birth this way," he added.
"This success represents a breakthrough in the field of fertility preservation," Grynberg said.
The new case involved a 34-year-old French woman who was infertile due to chemotherapy for breast cancer five years earlier. Before she started the cancer treatment, doctors removed seven immature eggs from her ovaries and used IVM to mature the eggs in the lab.
The mature eggs were preserved using vitrification -- rapid freezing of the eggs in liquid nitrogen to reduce the risk of ice crystals forming and damaging the cells.
When it was confirmed that the woman was infertile due to her cancer treatment, stimulation of her ovaries to prompt them to produce more eggs was ruled out because the hormones used in that approach could cause a return of her breast cancer. Instead, she and her doctors decided to use her frozen eggs.
Six eggs survived the thawing process and they were fertilized using ICSI (intracytoplasmic sperm injection). Fertilization was successful with five of the eggs and one embryo was transferred to the woman's womb. She became pregnant and nine months later she gave birth to a healthy baby boy on July 6, 2019.
"Fertility preservation should always be considered as part of the treatment for young cancer patients," Grynberg said. "[Mature] egg or embryo vitrification after ovarian stimulation is still the most established and efficient option. However, for some patients, ovarian stimulation isn't feasible due to the need for urgent cancer treatment or some other contraindication," he explained.
"IVM enables us to freeze eggs or embryos in urgent situations or when it would be hazardous for the patient to undergo ovarian stimulation," Grynberg added, and the technique is also "not associated with a risk of cancer recurrence."
One fertility expert in the United States agreed that the successful birth marks a new milestone.
"This is an extraordinary advancement in our field," said Dr. Christine Mullin, chief of the Northwell Health Fertility Center, in Manhasset, N.Y. It gives another viable option to "women seeking to preserve their fertility prior to treatments like chemotherapy or surgery."
Mullin believes the technique's use might someday be extended far beyond cancer patients.
If proven safe and feasible over time, the use of immature cells to preserve fertility could "make it a viable treatment for all patients undergoing fertility treatments -- eliminating the use of fertility medications and therefore reducing costs and the risk of ovarian hyperstimulation," she said.
The American Cancer Society has more on fertility and cancer.