METHODS: Cervical HPV testing was undertaken in pregnant women over 36 weeks of gestation, and mouth secretions and oral mucosa of neonates were tested for HPV immediately after delivery. HPV-positive neonates were rechecked 2 months postpartum to identify the persistence of HPV infection. In HPV-positive mothers, the placenta, cord blood and maternal peripheral blood were also analysed for HPV to confirm whether transplacental HPV infection occurred.
RESULTS: HPV was detected in 72 of 469 pregnant women (15.4%) and in 15 neonates (3.2%). Maternal HPV positivity was associated with primiparity and abnormal cervical cytology. The rate of vertical transmission was 20.8%, and all HPV-positive neonates were born from HPV-positive mothers. Vertical transmission was associated with vaginal delivery and multiple HPV types in the mother. Neonates with HPV showed a tendency for higher maternal total HPV copy number than neonates without HPV, but this difference was not significant (p=0.081). No cases of HPV infection were found in the infants at 2 months postpartum, and no HPV was detected in placenta, cord blood or maternal blood.
CONCLUSIONS: Vertical transmission of HPV is associated with vaginal delivery and multiple HPV types in the mother; however, neonatal HPV infection through vertical transmission is thought to be a transient.