Contraceptive methods and risk of pelvic endometriosis.

ABSTRACT

PIP: In northern Italy, physicians compared data on 376 women with laparoscopically or laparotomically confirmed pelvic endometriosis with data on 522 age-matched controls admitted for acute nongynecologic and nonobstetric conditions to the same hospitals to examine the association between contraceptive methods and pelvic endometriosis. Cases were more likely to have ever used oral contraceptives (OCs) than controls (40.3% vs. 29.7%; relative risk [RR] = 1.6), but the risk was limited to former OC users (RR = 1.7 vs. 0.9 for current users). There was no clear association with duration, recency and latency of OC use and risk of endometriosis. The relative risk of endometriosis for ever users of the IUD was 1.3. Duration of IUD use was not associated with endometriosis risk. Use of barrier methods was not correlated with risk of endometriosis (RR = 0.5). Before making any conclusions on the association between use of contraceptive methods and pelvic endometriosis, one should consider possible selection and other biases when interpreting epidemiologic data. For example, painful menstruation is a common symptom of endometriosis and a major indication for OC use. Thus, women with endometriosis-induced dysmenorrhea tend to be ever OC users.