The purpose of this study was to demonstrate if decreased fertility could be shown in women whose previous pregnancy had been terminated by a legally induced abortion. In 7 270 pregnant women fertility was measured as the time elapsed from the couple started sexual intercourse without using contraception to the present pregnancy. This interval was called "the latent period" and fertility was defined as reduced if it was longer than one year. In women whose previous pregnancy had been terminated by legally induced abortion subsequent decreased fertility could not be shown when compared with women whose previous pregnancy had ended in a live birth, the frequency of a latent period longer than one year not differing between these groups. When induced abortion had been complicated by pelvic inflammatory disease the frequency of a latent period more than one year was found to be higher than in women without this complication.