doctors often warn women who have breast cancer not to get pregnant. Since estrogen is believed to stimulate tumor growth, nine months of elevated levels of the hormone seem just too big a risk. But a study conducted by scientists in Copenhagen suggests that the risk may be worth taking. Using the Danish Cancer Registry and the National Birth and Induced Abortions Registries, the researchers coordinated the databases and found that 5,725 women of childbearing age had been treated for breast cancer. They examined their reproductive histories. Taking into consideration such factors as age at diagnosis they found that the 84 women who went through full-term pregnancies actually showed a slightly decreased rate of mortality than those who did not become pregnant.

Critics of the study caution that it couldn't account for every variable, and that the sample is small. Author Niels Kroman says, "I'm happy we found this trend toward reduced risk, because it means the chance that we could have overlooked an increased risk is very small.' For cancer patients, that could be very reassuring.