An international team of fertility experts is asking doctors to monitor carefully the pregnancies and babies of all women who undergo egg retrieval and IVF after cancer chemotherapy.
Research on mice has shown that cylophosphamide - a commonly used drug belonging to a group of anti-cancer agents known as alkylating agents - causes fetal malformations and pregnancy failure. More importantly, the new study reveals that the effect on the embryo is influenced by the stage of egg follicle development at the time of exposure to the drug.
Although the researchers stress that there is no evidence as yet to suggest equivalent treatment-induced problems in human eggs, they believe that their findings indicate that eggs collected from women within six to 12 months of treatment could be particularly vulnerable to damage.
The study has been carried out by Dr Dror Meirow at the Rabin Medical Centre and Schneider Children Medical Centre in Israel, Drs Michal Epstein and Hadassa Lewis at the Hadassah Medical Centre in Jerusalem, Dr David Nugent at the University of Leeds in the UK, and Professor Roger Gosden at the Royal Victoria Hospital, Montreal, Canada.
The results are reported today* (Thursday 29 March) in Europe's leading fertility journal, Human Reproduction.
Although research has already shown that cyclophosphamide can induce genetic damage and has raised concerns about pregnancies in cancer survivors and the health of the children, all the studies on pregnancy outcome to date have been reassuring, suggesting that these concerns are unfounded. However, the research was on women who became pregnant a long time after treatment stopped.
New reproductive techniques mean that many centres offer egg retrieval and embryo freezing before starting cancer treatment that is likely to result in infertility. But delaying life-saving treatment while patients undergo egg-retrieval cycles may be inadvisable. So some centres now offer IVF and embryo cryopreser
Contact: Margaret Willson
European Society for Human Reproduction and Embryology