The researchers used transvaginal ultrasounds, taken at the beginning of the menstrual cycle, to measure the volume of the women's ovaries and to count the number of antral follicles (follicles that may mature and subsequently ovulate). They found that women in the ALL group had ovaries which were significantly smaller than the control group (12.3 ml in total volume compared with 13.7ml), and the total number of antral follicles per ovary was significantly lower in the ALL women, with an average of eight per ovary compared with 11 in the control group.
Dr Larsen said: "Although these long-term survivors of childhood leukaemia have an apparently normal ovarian function, our results suggest that the chemotherapy has reduced the numbers of follicles in the ovaries. Therefore it is important that women who have survived childhood leukaemia should receive careful and individual fertility counselling as their reproductive life may be shortened."
She said that it was not possible to give a precise estimate of how much shorter the women's reproductive life might be. "At present, in our hospital, we recommend to all female survivors of childhood cancer with normal ovarian function that they should try to have their first child before they are 30. However this recommendation is not made on the basis of any scientific findings. The majority of long-term survivors attend regular follow-up check-ups at our outpatient clinic and we are considering offering fertility counselling to them between the ages of 18 and 20.
"The important message to come from this research is women who have survived ALL can become pregnant and have babies and they are doing so. However they should not postpone childbearing, and it might be that they should consider becoming mothers before pursuing a career," concluded Dr Larsen.
Contact: Emma Mason
European Society for Human Reproduction and Embryology