June 29, 2009
New Ovarian Transplant Technique Successful
A new, two-step method of ovarian transplant has had excellent results, giving women a greater ability to conceive after cancer treatment or when older, doctors announced Monday.
The technique successfully and quickly restored ovarian function enabling two patients to become pregnant.Scientists have performed ovarian transplants in women with cancer before, since chemotherapy often leaves them infertile. The ovaries are removed before the toxic treatment begins in order to re-implant them later.
Up to this point, cost and uncertainty yielded only a handful of successful transplants, but since women with diseases have limited options, they found it worth a shot.
Now, recent advances in the preservation and surgical implantation of ovaries could make the procedure more widely available, to promote fertility even as women get older. It has become increasingly common for women to put off having children until their 30s and 40s, an age range that experiences more fertility issues.
This means that women in their 20s or 30s could theoretically have an ovary taken out and frozen, and then have it re-implanted down the road when they are ready to have children.
"We are in the middle of an infertility epidemic," said Dr. Sherman Silber, director of the St. Louis Infertility Center in Missouri, one of the experts behind the research. "With these new techniques, we could dramatically expand our reproductive lifespan."
The research was reported at a meeting of the European Society of Human Reproduction and Embryology in Amsterdam.
Silber and colleagues observed the number of eggs lost or preserved in fresh and frozen ovarian tissue of 15 young women prior to cancer treatment. The doctors were unable to find a difference in the number of eggs in fresh tissue and in ovaries frozen using the new ultra-fast technique.
With the traditional method, about half of a woman's eggs were lost due to the slow-freezing methods of preserving ovaries.
Dr. Pascal Piver of Limoges University Hospital in France reported on a new surgical technique to transplant ovaries in another research study.
Dr. Piver and colleagues decided to solve one of the biggest problems of ovarian transplantation: the low response to stimulation caused by insufficient vascularization of the transplanted tissue.
Piver and colleagues approached the problem by dividing the transplant into two procedures. They did an initial graft of small pieces of ovarian tissue to encourage blood vessels to grow and put it in place three days before the real transplant. This paved the way for the ovary to become fully functional in a shorter time scale than would be possible if all the tissue were to be transplanted at the same time.
The technique was used in a French woman who had been unable to have children because of treatment for sickle cell anemia. She became pregnant naturally after just six months and in June, gave birth to a baby girl.
"She suffered menopause for eight and a half years before transplantation," said Dr. Piver.
"But after transplanting half of the frozen ovary, she recovered spontaneous ovulation in four months. Her right fallopian tube had been destroyed by the ovarian retrieval, and the function of the ovary and hence the chances of pregnancy are limited in time. Hence we decided to collect the highest number of eggs we could, and carry out an IVF procedure on this patient.
"Six months after the operation, we transferred two blastocysts. A total of 22 oocytes were retrieved and produced 16 embryos, which in turn produced seven blastocysts. Unfortunately the first time round this patient developed an ectopic pregnancy, but she is now pregnant again."
Pasquale Patrizio, of Yale University, who performs ovary transplants but was not connected to either study said, "All of this research is a step in the right direction"¦if we really have these techniques under control, maybe we can spread this technology to many more women."
But Patrizio says that doctors need to know how an ovary taken from a woman years ago will fare once it is re-introduced.
"If I take an ovary from a woman who's 30 and then re-implant it 15 years later, will it function as if it's a 30-year-old's ovarian tissue, or will it reset to become 45?" he asked.
Experts expect that the mere possibility of healthy women undergoing ovary transplants would probably ignite controversy.
"This is not an experimental procedure for cancer patients anymore," Silber said. "The question is whether more women should be able to have this option."
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