A large-scale, methodologically rigorous Danish study has concluded that, among women of similar age and reproductive history, those who have had one or more induced abortion are no more likely than women with no abortion history to develop breast cancer. The reliability of previous studies of this association has been limited by many women's reluctance to be truthful about their abortion history. This potential source of bias was overcome, in the present study, through the linkage of data from the Danish Cancer Registry with information from the National Registry of Induced Abortions, which provides statistics on the patient's age at the time of a pregnancy termination as well as the duration of pregnancy at abortion. Although the relatively small group of women who had abortions after 12 weeks of pregnancy demonstrated a slightly increased risk of breast cancer compared with women with earlier terminations or no abortion history, the number of women involved was too small to permit any generalizations at this time.
