BioNews reporting from the ESHRE conference, Berlin:
Danish researchers have reported that they are on the verge of producing a pregnancy from frozen-thawed human ovarian tissue, while in Belgium it transpires that a woman is already 25 weeks pregnant following similar treatment - the first time this treatment has ever led to a pregnancy.
Dr Claus Yding Andersen, from the University of Copenhagen, told the conference that an ovary was removed from a 32-year old woman, diagnosed with Hodgkin's lymphoma, who was about to undergo chemotherapy and radiotherapy that would make her infertile. The ovary was frozen and then thawed after two years, when the woman was no longer receiving cancer treatment. In April 2003, six strips of the ovarian tissue were grafted to the woman's remaining ovary, which had stopped functioning, becoming menopausal as a result of the cancer treatment.
Eight weeks later, as a result of the grafts, ultrasound and hormone tests showed that the ovaries had begun to function again, and her menstrual cycle restarted. Since then, the ovary has produced eggs, but three attempts to establish a pregnancy in the woman have been unsuccessful. The first cycle used IVF with ICSI (intracytoplasmic sperm injection) in an attempt to create an embryo, but the egg did not fertilise. In the second, intra-uterine insemination (IUI) was attempted, but this also failed. In the third attempt, again using ICSI (intracytoplasmic sperm injection), a two-celled embryo was created on 1 June 2004. This was transferred to the woman's uterus, but failed to implant. Dr Andersen said, however, that the team would keep trying, and that 'it is only a matter of time before a woman becomes pregnant and gives birth to a child after having a thawed ovarian transplant'.
However, it emerged at the conference press briefing that a pregnancy after the use of frozen-thawed ovarian tissue had actually already been established, in another woman who had undergone treatment for Hodgkin's lymphoma. The baby, a girl, was conceived naturally after ovarian tissue grafts restored the mother's fertility, and is due at the beginning of October. The team, from Louvain University in Brussels, say, however, that it is not yet established whether the woman's remaining ovary started to function normally again, or if the egg that was fertilised came from the grafted ovarian tissue. Professor Jacques Donnez, leader of the research team, confirmed the story on Belgian radio, saying the woman 'is pregnant', adding 'it's her child genetically, growing from her tissue, and she fell pregnant completely naturally'.
In March 2004, a team at Cornell University reported the first human embryo produced following a frozen-thawed ovarian tissue transplant, but no pregnancy resulted. In October 2003, the first primate birth following transfer of frozen-thawed ovarian tissue - a rhesus macaque monkey - was announced. At the time it was hoped that the technique would soon lead to a human birth. Now it looks like the Belgian team will be the first to make such an announcement, however, details of the pregnancy have yet to appear in a scientific publication.