For the first time, a woman has given birth to two healthy children as a result of one transplantation of ovarian tissue: once by artificial means, once naturally, Danish researchers say.
In December 2005, Stinne Holm Bergholdt received a transplant in of six strips of her own ovarian tissue, which she had frozen before starting chemotherapy treatments for cancer.
She gave birth to a girl in February 2007 after fertility treatments, but when she returned to the clinic for more treatments in January 2008, she discovered she had already become pregnant naturally.
Bergholdt gave birth to another girl in September 2008, Dr. Claus Yding Andersen of the University Hospital of Copenhagen and colleagues reported online in Human Reproduction.
"This study shows that transplantation of just six pieces of frozen/thawed ovarian cortext to a woman who experienced chemotherapy-induced menopause can result in the production of fully mature oocytes for a period exceeding four years and that the capacity to sustain embryogenesis and give birth to healthy children remains," the researchers wrote.
Bergholdt, who is from Denmark, was diagnosed with Ewing's sarcoma in 2004, when she was 27. Before chemotherapy, part of her right ovary was removed and frozen so that she could try to conceive naturally. Her left ovary had been previously removed because of a large mass.
As expected, chemotherapy initiated menopause, but in December 2005, six strips of ovarian tissue were transplanted back on to what remained of her right ovary. The organ began to function normally and after mild ovarian stimulation, she became pregnant and gave birth to Aviaja in February 2007, with the help of IVF treatments.
When she returned for more IVF treatments in January 2008, she learned she was already pregnant naturally.
"This suggests that there is a relatively good chance of restoring natural fertility following the transplantation of ovarian tissue and that the cryopreservation and transplantation procedure does not in itself harm normal ovarian function," the researchers wrote.
Andersen said that Bergholdt has more ovarian strips in storage and may even be able to remain functional for as long as 40 years if stored properly.
A total of nine children have now been born as a result of transplanting frozen and thawed ovarian tissue, including Bergholdt's two girls. Three were conceived naturally.
The procedure is based on the fact that all follicles containing eggs are located in the outer millimeter of the ovary, which can be sutured to the recipient's medulla just like a full-thickness skin graft. It has become more popular as more young women have cancer treatments that are toxic to their reproductive organs.
Other researchers have noted, however, that the graft generally loses two-thirds of its follicles from blood deprivation after transplant, reducing its lifespan. But even if the graft eventually fails, surgeons can re-transplant more strips of tissue as long as enough has been frozen in storage.
An alternative to ovarian tissue transplant is full ovarian transplant, which has been performed several times, primarily between identical twins.
The researchers concluded that the findings "extend the number of children born as a result of transplanting frozen/thawed ovarian tissue to nine globally and encourage a continued effort to develop this technique as a valid method for fertility preservation."