Human Papillomavirus (HPV) is the most common sexually transmitted infection. While most infections clear on their own, certain types can cause serious health issues, including various cancers and genital warts. Expectant parents often ask if this virus can be passed from a mother to her child. Vertical transmission of HPV is biologically possible, but the overall risk of the virus causing a clinically significant disease in the infant is rare.
How HPV Vertical Transmission Occurs
The primary way a mother passes HPV to her infant is through contact with infected tissue during the birthing process. This is called intrapartum transmission, occurring when the fetus contacts HPV-infected cells in the cervix or vagina while traveling through the birth canal. The risk of exposure increases significantly if the mother has active genital warts at the time of delivery, and mothers who transmit the virus often have a higher viral load.
Postnatal transmission is less common and may occur through exposure to maternal lesions or potentially via breast milk, though the latter is debated. Antepartum, or in utero, transmission is also possible, involving the virus crossing the placenta. HPV DNA has been found in placental tissue and umbilical cord blood, suggesting spread from the mother’s bloodstream. However, this route is considered less frequent than exposure during delivery.
The detection of HPV DNA in a newborn is not always clinically significant. Many infants who test positive for the virus shortly after birth clear the infection spontaneously within the first few months or years of life. The clinical relevance of transient HPV detection in newborns is still under investigation.
Health Conditions Resulting from Infant HPV Exposure
The most serious, though rare, consequence of vertical HPV transmission is Juvenile-onset Recurrent Respiratory Papillomatosis (J-RRP). This condition involves the growth of benign, wart-like tumors in the respiratory tract, most commonly on the vocal cords and larynx. J-RRP cases are associated with low-risk HPV types 6 and 11, which also cause most genital warts.
Symptoms of J-RRP often start with persistent hoarseness or a weak cry in the infant or young child. Growing papillomas can obstruct the airway, causing chronic cough, difficulty breathing, and respiratory distress. Since the tumors often regrow after removal, children with J-RRP require repeated surgical procedures throughout childhood to maintain a clear airway and preserve their voice.
Other less common manifestations of infant HPV exposure include genital warts, also caused by types 6 and 11, and rarely, oral or conjunctival papillomas. The risk of an infant developing any clinical disease, including J-RRP, remains low, with an estimated annual incidence of about two to four cases per 100,000 children in the United States.
Strategies for Reducing Transmission Risk
Primary prevention against HPV infection is achieved through vaccination. Receiving the HPV vaccine before becoming sexually active is the most effective way to reduce the risk of future transmission to a child. The vaccine protects against high-risk types that cause cancer, as well as low-risk types 6 and 11 that cause genital warts and J-RRP. Vaccination is not recommended during pregnancy but can be administered postpartum.
Medical guidelines for managing HPV in pregnant women focus on minimizing the child’s exposure without unnecessary intervention. Routine screening, such as Pap smears, is maintained during pregnancy, and colposcopy may be performed if results are abnormal. Aggressive treatment of cervical lesions or genital warts is avoided until after delivery, as warts often regress spontaneously postpartum.
A Cesarean section is not routinely recommended for all HPV-positive mothers. C-sections should only be performed to prevent HPV transmission if the mother has massive or obstructive genital warts that would impede the infant’s passage through the birth canal. In most cases, the risks of surgical delivery outweigh the low risk of HPV transmission. After delivery, parents and pediatricians should watch for early signs of J-RRP, such as a persistent change in the child’s voice or breathing difficulties, as prompt diagnosis is crucial.