Before the woman was treated, Jacques Donnez and colleagues at Catholic University of Louvain in Brussels took five samples, each about a quarter of an inch wide and half an inch long, from her left ovary. Four of those were chopped into a total of 70 tiny cubes of tissue, each about one-sixteenth of an inch square. The cubes and the single strip were then frozen in liquid nitrogen.
The woman received six months of chemotherapy and radiation treatments, after which tests indicated her ovaries had stopped functioning.
Early last year, the woman decided she wanted to have a child, so the surgeons transplanted the one tissue strip and all of the cubes into a small furrow they created in the woman's pelvic space, close to her right ovary. Five months later, tests indicated those tissues were producing hormones, and she started having menstrual cycles. After another five months, she became pregnant without technical intervention.
Kutluk Oktay, a reproductive endocrinologist at Cornell University's Weill Medical College in New York, who has pioneered the use of frozen ovarian tissue, said he was concerned about the lack of definitive proof that the egg that led to the pregnancy came from transplanted tissue. But he said he was "cautiously optimistic" that the experiment was successful.
Tests during the years after the woman's cancer treatment hinted that her left ovary might have produced eggs as many as three times. But ultrasound images indicated that the pregnancy occurred after a mature egg erupted on the woman's right side, where the transplanted tissues were. By contrast, there was no sign of egg production in either ovary during the cycle leading to the pregnancy -- "crucial" evidence, the doctors reported, that the child was conceived from an egg that matured within one of the transplanted tissues.
That egg would then travel down a fallopian tube and be fertilized during sex.
"Our findings open new perspectives for young cancer patients facing premature ovarian failure," the team wrote in today's online version of the British medical journal the Lancet, which posted the report within hours of the girl's birth.
Although the baby appears healthy, no one knows how freezing affects immature eggs. R. Alta Charo, an associate dean of law and a bioethicist at the University of Wisconsin at Madison, said experiments such as the Belgian one need special scrutiny, because "the risks are carried not just by the patient but also by the next generation."
