Double the risk of ovarian malignancy after 15 years in women who received in vitro fertilization: A large cohort study published in the October 26, 2011 issue of Human Reproduction showed that women treated with in vitro fertilization (IVF) had twice the risk of ovarian malignancy after 15 years compared with those who did not receive IVF, but no significant increase in the risk of invasive ovarian cancer was seen over 15 years. Leeuwen et al. conducted a follow-up study of the risk of ovarian malignancy in 9,146 women treated with IVF during 1983-1995 versus 6,006 women with infertility disorders who were not treated with IVF, and compared it to the incidence in the general population. The median follow-up time was 15 years, and the results showed that ovarian malignancies were detected in 61 women in the IVF treatment group, nearly half of whom had junctional tumors, compared with 15-30% of the general population of women under 50 years of age. After adjusting for potential confounders such as age, number of births, and cause of infertility, the risk of junctional ovarian tumors was significantly higher in the IVF-treated group than in the low-fertility control group (HR, 4.23), and the overall risk of all ovarian malignancies was significantly higher than in the control group (HR, 2.14). The risk of invasive ovarian cancer was not significantly increased in the IVF-treated group compared with the control group (HR, 1.51), but the risk of invasive ovarian cancer was significantly increased after 15 years of IVF treatment compared with the general population, with a standardized incidence ratio (SIR) of 3.54. This study reveals one aspect of the effect of IVF on the development of tumors in the distant future, which should be informed at the time of IVF counseling. The study revealed one aspect of the effect of IVF on the development of distant tumors, which should be informed during IVF counseling.