Background: The knowledge on vertical human papillomavirus (HPV) transmission is limited. We aimed to determine whether HPV transmission from parents to their offspring occur before or during birth.

Methods: Altogether, 321 mothers, 134 fathers and their 321 newborn offspring from the Finnish Family HPV study cohort were included. Parents' genital and oral brush samples and semen samples were collected for HPV testing at baseline (36 weeks of pregnancy). Oral, genital and umbilical samples from the newborn and placenta samples were collected for HPV testing immediately after delivery. HPV risk for the newborn was calculated from mother's and father's HPV status by using logistic regression analyses.

Results: Concordances between mothers' and their newborns' HPV genotype at any site were statistically significant with HPV6, HPV16, HPV18, HPV31 and HPV56; Odds Ratios (OR) ranged from OR 3.41 (95% CI: 1.80-6.48) for HPV16 to OR 634 (95% CI: 28.5-14087) for HPV31. Father-newborn HPV concordances were statistically significant with HPV6 and HPV31; OR 4.89 (95% CI: 1.09-21.9) and OR 65.0 (95% CI: 2.92-1448), respectively.ConclusionsThe genotype-specific HPV concordance between parents and their newborn is suggestive for vertical HPV transmission. However, transmission from the father to the newborn remains more uncertain.