Does Active Oral Sex Contribute to Female Infertility?

Based on recent, historical, and circumstantial evidence, we present a multifactorial hypothesis that has potential direct implications on the epidemiology and management of chlamydial infection and disease in humans. We propose that (1) like its veterinary relatives, the oculogenital pathogen Chlamydia trachomatis evolved as a commensal organism of the human gastrointestinal (GI) tract primarily transmissible via the fecal-oral route; (2) in the modern era, C. trachomatis causes "opportunistic" infection at non-GI sites under conditions driven by improved sanitation/hygiene and reduced fecal-oral transmission; and (3) the rise in the practice of oral sex is contributing to the increased prevalence of C. trachomatis in the human GI tract. Infectious organisms produced in the GI tract and reaching the rectum may then chronically contaminate and infect the female urogenital tract, thereby potentially contributing to the most serious sequelae of chlamydial infection in women: pelvic inflammatory disease, ectopic pregnancy, and tubal factor infertility.