Oral contraceptive and benign ovarian tumors.

Whether use of combined oral contraceptives (OC) protects against benign ovarian tumors is unknown. A case-control study of pathologically confirmed benign ovarian tumors was conducted in the New York City area and included cases diagnosed from January 1, 1992, to December 31, 1993, and controls identified by random digit dialing. There were 196 cases with serous adenomas, 176 with teratomas, 311 with endometriomas, and 65 with mucinous adenomas. Interview data were used to determine contraceptive use. Ever use of OC was associated with a decreased risk of these benign tumors (age- and hospital-adjusted odds ratio = 0.79, 95% confidence interval: 0.60, 1.05). In histologic subgroup analyses, the risk of ovarian tumors was reduced for both current and past OC users. Among tumor subtypes, the risk reduction was greatest for women who had endometriotic lesions. The risk reduction also was greater for women who had used OC for more than 24 months. Protection against benign ovarian tumors may be an additional noncontraceptive benefit of OC use.