Pregnancy and Chemo a Risky Combo
March 28, 2001 -- Women who develop cancer are often faced with the possibility of being left unable to bear children as a result of chemotherapy-induced infertility. One option is to undergo an in vitro fertilization procedure, or IVF, to have some eggs removed and embryos created and frozen before starting chemotherapy. The embryos can then be implanted after cancer treatments are finished.
This option has been used successfully for several years, and healthy babies have been born to women who otherwise might not have been able to conceive.
Despite this, some doctors are allowing women to undergo IVF after exposure to chemotherapeutic drugs, such as during breaks in the chemotherapy cycle or once they've gone into remission after receiving certain types of chemotherapy not thought to cause infertility.
However, a new report from researchers in Israel, the U.K., and Canada suggests this approach is risky and can increase the risk for genetic damage in the offspring. The report, which appears in the March 29 issue of the journal Human Reproduction, involved groups of mice exposed to cyclophosphamide, a widely used chemotherapeutic and immunosuppressive drug.
"To date, there isn't any epidemiological data suggesting that former cancer patients who received high doses of chemotherapy are at greater risk for producing babies which have any defects," says Roger G. Gosden, MD, one of the co-authors of the report. "However, the techniques that we can now apply to looking for genetic damage are much greater and our study ... indicates that we should be alert to the possibility [of such damage]. And if it is a real hazard, then we have to consider more seriously the idea of protecting the patient's [eggs] prior to chemotherapy.
"I don't want to be alarmist about this," he tells WebMD, "but I think these sorts of studies should signal to the research community to keep a close eye on children of former cancer patients. We can't always extrapolate from animal studies to humans, but the stakes are really quite high because there are more and more patients who are receiving very high-dose treatment and surviving the treatment and wanting to have a family afterward."
In general, Gosden says, it's best that egg retrieval be carried out before most types of chemotherapy are begun. Although it is usually possible, there are certain types of leukemias that require starting treatment immediately, which could make it difficult for women to have the embryo-removing procedure done in time. Not wanting to delay starting chemotherapy has been a main reason doctors have performed egg retrieval and IVF with embryo freezing after chemotherapy has begun.
Gosden also says scientists have assumed that the children produced so far from embryos created by IVF prior to their mother's cancer treatment are healthy. But he says more research is needed to follow these children throughout their lives to make sure they don't develop health problems later in life. The same goes for women who have had natural pregnancies years after cancer treatment.