"The precise route of vertical transmission remains unclear. Several studies have reported that the risk of vertical transmission is increased with vaginal delivery, suggesting that perinatal transmission occurs as the fetus passes through an infected birth canal [6], [23], [24]. However, other investigators have reported that cesarean delivery is not protective against perinatal transmission [22], suggesting that route of delivery may not be a critical risk factor. In the current study, the risk of HPV DNA detection in neonates was not significantly reduced in women delivered by cesarean delivery. Indeed, more HPV DNA-positive neonates were born by cesarean than vaginal delivery (p<0.05, Table 1). These data suggest that other routes of vertical transmission may exist. "
"In the prior studies of Park et al. and Rombaldi et al., all infants who were HPV positive at birth subsequently tested HPV negative at both 6 months and 12 months of life [10], [31]. However, other reports have shown that HPV can be detected persistently in infants for months and years after birth, suggesting that this is not simply contamination with maternal virus [12],
. Although HPV is known to cause clinical disease, including benign orogenital lesions (warts) as well as cancer of the cervix and head and neck, it is still unclear how often infantile HPV infection progresses on to clinical disease [4]. If vertical transmission does occur and if the virus can persist in a dormant state for many years, then mother-to-fetal transmission may be laying the blueprint for cancer development later in life in many organ systems."
"It has recently been suggested that a subset of head and neck squamous cancers, especially oropharyngeal cancer, is HPV-related [5]. Indeed, 40–80% of oropharyngeal squamous cell cancers in the US are positive for HPV 16 [2]–[5]. In spite of the importance of HPV in oropharyngeal cancer, the epidemiology and natural history of oral HPV infection is not well understood. "
"In conclusion, HPV DNA can be detected in 5% of neonates born to healthy women, and is associated with detection of HPV in mothers during any of the three trimesters of pregnancy. This observation has major implications for our understanding of the route and timing of HPV mother-to-fetal transmission.