History of long-term use of depot-medroxyprogesterone acetate in patients with cervical dysplasia; case-control analysis nested in a cohort study. The New Zealand Contraception and Health Study Group.

Histories of use of depot-medroxyprogesterone acetate (MPA) given by women entering a previously-reported prospective study of risk of cervical dysplasia, including carcinoma, have been evaluated. Over a six-year follow-up period, 348 of the 7199 enrolled women developed cervical dysplasia diagnosed by cytology and confirmed by histology or DNA analysis. Use of MPA prior to entry into the study was reported somewhat more commonly and for somewhat longer periods by the women who developed confirmed dysplasia than by those who did not. However, this association was accounted for entirely by the fact that women who reported use of MPA, particularly at an early age, tended to carry a number of known strong risk factors for dysplasia, specifically, first intercourse at an early age, multiple sex partners and cigarette smoking. These findings indicate that the lack of relationship of MPA use to risk of cervical dysplasia, noted previously for women whose median duration of use within the formal study period was about 2 years, extended to the same women who used MPA prior to the study period--even to those whose duration of prior use was 4 years or more.