Healthy Belgian Baby Is Born Using Harvested Ovarian Tissue
Belgian physicians have for the first time produced a healthy infant conceived using ovarian tissue that had been frozen to protect it from the lethal effects of chemotherapy.
After the tissue was reimplanted, the woman conceived naturally, and Tamara Touirat, 8 pounds, 4 ounces, was born Thursday evening at St. Luke’s Hospital in Brussels -- seven years after her mother began chemotherapy.
The finding, published online today by the journal Lancet, gives hope to hundreds of thousands of women who in the past would have lost their chance to have children because their cancer treatment rendered them infertile. But it may be years before the technique can be used routinely.
“This is something that we have been talking about for a long time
Experts cautioned that there was a small possibility that the pregnancy resulted from some ovarian tissue that was not destroyed by the chemotherapy.
“We can’t say absolutely that the pregnancy was from the transplanted tissue,” said Dr. Zev Rosenwaks of the Weill Medical College at Cornell University.
“Women can occasionally regain reproductive function [after chemotherapy].”
Nonetheless, he added, the “most compelling evidence” for the success of the procedure was evidence obtained by laparoscopy that follicles in the transplanted tissue were actually producing eggs.
Women who are rendered infertile by cancer treatments have few options to bear children later.
Before their cancer treatments, they can have eggs extracted and frozen to be fertilized later and implanted. But the technique has a low rate of success because it is difficult to safely thaw the eggs.
A more successful strategy has been to freeze fertilized eggs, which for unknown reasons are easier to preserve. But the process of extracting an egg that is ready to be fertilized takes time -- time that is often not available if a woman must start chemotherapy quickly.
Prepubescent girls pose a special problem because their immature eggs cannot be collected.
The result is that many women who have cancer treatments are left infertile.
Ovarian tissue can be easily collected. The tissue, which contains hundreds or thousands of eggs, stores well, said Dr. Roger Gosden of Cornell.
“What we can’t do very well yet is grafting those tissues back into the donor,” Gosden said. The ovary has a high concentration of blood vessels to support the tissue, and researchers have had trouble inducing new blood vessels to support the grafts.
Researchers have taken two approaches to the transplants.
Most have transplanted the thawed tissue under the skin of the arm or in the abdomen, then extracted eggs and subjected them to in vitro fertilization. Dr. Kutluk Oktay and his colleagues at Cornell reported in March that they had used this technique to create a four-celled embryo that was implanted into a woman. The pregnancy did not take, however.
Dr. Jacques Donnez of the Catholic University of Louvain chose to transplant the tissue back into the ovary, where it was more likely to establish a blood supply and where it could reestablish a normal reproductive cycle.
His team’s patient, Ouarda Touirat, was 25 when she came to them in 1997 with stage IV Hodgkin’s lymphoma. With her consent, doctors collected five samples of tissue from her left ovary and froze them.
After the successful completion of her chemotherapy, Touirat was infertile. She was given hormone replacement therapy for two years, but it was stopped because she wanted to become pregnant.
In 2001, Donnez’ team implanted the ovarian tissue. Five months later, Touirat began ovulating. Eleven months after the transplant, her husband impregnated her. The baby was delivered full-term Thursday evening in Belgium.
“This is an exciting advance,” said Dr. Arthur Wisot of Reproductive Partners Medical Group in Beverly Hills, author of “Conceptions & Misconceptions.” “It’s only one patient ... but this holds out hope for a way for women who have to go through chemotherapy and radiation to preserve their fertility.”
Donnez’ team reported that they had preserved ovary tissue from 146 patients who subsequently began chemotherapy. The tissue has been reimplanted in one other patient, but she has not become pregnant yet.