Husby A, et al. - Via a nationwide register based cohort study of 2,311,332 Danish women born from 1935 to 2002, researchers investigated the correlation between pregnancy term and risk of endometrial cancer. During 573,47,622 person years of follow-up, of 947,650 pregnancies, 6,743 women developed endometrial cancer. Following adjustment for age, period, and socioeconomic factors, a first pregnancy was related with a significantly decreased risk of endometrial cancer, whether it ended in induced abortion or childbirth. Each subsequent pregnancy was related to an additional decline in risk, whether it ended in induced abortion or childbirth. Term of pregnancy, age at pregnancy, spontaneous abortions, obesity, maternal birth cohort, fecundity, and socioeconomic factors did not alter the outcomes. In conclusion, the risk of endometrial cancer was reduced despite whether a pregnancy ended shortly following conception or at 40 weeks of gestation. This decrease in risk could be described by a biological process occurring within the first weeks of pregnancy, as pregnancies ending in induced abortions were correlated to comparable decreases in risk as pregnancies ending in childbirth.