The impact of pregnancy on human papillomavirus (HPV) natural antibody levels is not fully understood. We tested the seroprevalence and levels of HPV 6, 11, 16, 18 and 45 antibodies at different time points among 89 women with a second pregnancy and 238 nonpregnant women during their 36-month followup. All participants were unvaccinated for HPV and pregnant at the enrollment of the study. Serum samples were collected from the mothers at baseline and at the 12-month, 24-month, and …