A case-control study of ovarian cancer in relation to infertility and the use of ovulation-inducing drugs.

The authors conducted a population-based, case-control study among women aged 35-54 years to assess the influence of infertility and use of ovulation-inducing drugs on ovarian cancer risk. The study was conducted from 1994 to 1998 in three regions (metropolitan Atlanta, Georgia, Detroit, Michigan, and Seattle, Washington) and included 378 cases and 1,637 controls. Data were obtained through in-person interviews, and analysis was conducted using unconditional logistic regression. Among parous women, the authors observed no association of cancer risk with a history of infertility, medical evaluation for infertility, specific types of infertility, or use of ovulation-inducing drugs. Among nulliparous women, risk was increased among women with a history of infertility (odds ratio = 1.6, 95% confidence interval: 1.0, 2.6), particularly when infertility first became manifest relatively late in reproductive life (for first infertility at > or =30 years of age: odds ratio = 2.2, 95% confidence interval: 1.1, 4.5); risk was not associated with medical evaluation for infertility, specific types of infertility, or use of ovulation-inducing drugs. Findings were similar when borderline and invasive epithelial tumors were considered separately. While the results of this study support the hypothesis that a subset of nulliparous women who experience infertility may be at increased risk of ovarian cancer, the reasons for this increase in risk remain unclear.