In either case the result would be detection of more lesions in OC users, but not actually more lesions. Cervical cancer develops slowly. Invasive cancer apparently occurs at the end of a slow progression of pre-invasive lesions. Hypothetically, OC use could have an independent effect or act as a cofactor at any stage. Research needs to explore why some pre-invasive lesions progress while most regress, and what role, if any, OCs play in progression.
Findings are mixed.
Studies have not consistently controlled for sexual behavior, however.