Risk factors for benign ovarian teratomas.

Risk factors for benign ovarian teratomas have been analysed in a case-control study conducted in Milan. Cases were women aged less than 65 years with a histologically confirmed diagnosis of benign ovarian teratoma who were admitted to a network of Obstetrics and Gynecology Departments in Milan. A total of 77 women aged 16-64 years were interviewed. Controls were women admitted to hospital for acute, non-gynaecological, non-hormonal and non-neoplastic diseases; 231 controls were interviewed (age range 15-64 years). Cases tended to be more educated: in comparison with women with less than 7 years of education, the estimated relative risk (RR) of ovarian benign teratoma was 1.6 and 2.5 respectively in women with 7-11 and 12 or more years of schooling, the trend in risk being statistically significant (chi 2(1) trend 5.39, P < 0.01). Four of the 77 cases (5.2%) and two of the 231 controls (0.9%) reported a history of infertility, with a corresponding RR of 8.3 (95% confidence interval 1.3-54.0). There was no clear relation between parity and risk of ovarian benign teratomas: in comparison with nulliparae, the estimated RRs were 1.1 and 0.7 respectively in women reporting one or two or more births (chi 2(1) trend 0.53, P = not significant). No relation emerged between marital status, age at menarche, menstrual cycle pattern, menopausal status, abortions, age at first pregnancy, oral contraceptive use and risk of ovarian benign teratomas.