Research Suggests Perinatal HPV Transmission Is Uncommon

Infection with vaginal human papillomavirus (HPV) is common among pregnant women; however, perinatal transmission to infants is infrequent, new study results suggest.

Findings were published in JAMA Pediatrics,¹ and data also showed no infection that was detected at the time of birth in the cohort persisted after 6 months.

“Although HPV was detected in placentas, it remains difficult to differentiate contamination vs true infection,” authors wrote.

HPV is the most common sexually transmitted infection and the leading cause of cervical cancer. The highest prevalence of the infection is found during the ages of peak fertility, which for most women are late teens through their late 20s.²

pregnancy, ultrasonic portrait of the fetus: © Astroid - stock.adobe.com

“Because of the potential for perinatal transmission of HPV, more information is needed on the frequency and dynamics of transmission, especially because recent evidence suggests that newborns may acquire HPV perinatally and that HPV may influence pregnancy outcomes,” researchers explained.

To address this knowledge gap, investigators carried out the Human Papillomavirus Perinatal Transmission and Risk of HPV Persistence Among Children (HERITAGE) study. Participants were recruited from November 2010 to October 2016, and follow-up visits were completed in June 2017.

All individuals were at least 18 years old and no more than 14 weeks pregnant. They were recruited from 3 academic hospitals in Canada.

For those with HPV-positive samples collected during their first trimester, additional samples were taken in the third trimester. Swabs and biopsies were used to test for HPV on placental samples of all participants. Researchers also tested for HPV in children at birth, after 3 months, and after 6 months.

Just over 1000 women took part in the study. The average participant age was around 31. At the time of recruitment, 40.3% of women had an HPV infection. Of the 422 women who tested positive, 280 had at least 1 high-risk genotype, the authors wrote, while 190 were coinfected with at least 2 genotypes.

Analyses also revealed these findings:

• HPV was found in 10.7% of placentas (95% CI, 8.8%-12.9%)
• Only 3.9% of biopsies on the fetal side under the amniotic membrane were positive for HPV
• Neonatal HPV detection (at birth and/or at 3 months) was 7.2% (95% CI, 5.0%-10.3%)
• The most frequent site of infection was the conjunctiva (3.2%; 95% CI, 1.8%-5.6%), the mouth (2.9%; 95% CI, 1.6%-5.2%), the genital area (2.7%; 95% CI, 1.4%-4.9%), and the pharynx (0.8%; 95% CI, 0.2%-2.5%)
• All HPV detected in children at the time of birth cleared before age 6 months

Most participants (84.9%) had not received an HPV vaccine. HPV-53, HPV-62, HPV-16, and HPV-89 were the most commonly detected genotypes.

“Among HPV-positive women in the first trimester, the percentage of women still infected with at least 1 of the same genotype in the third trimester was 72.2% (95% CI, 67.4%-76.5%), and the percentage of women in whom at least 1 new genotype was detected in the third trimester was 28.3% (95% CI, 24.0%- 33.1%),” the authors added.

Several factors can affect whether HPV is detected in the placenta, including the mother’s HPV status during pregnancy and the mode of delivery.

The researchers did not test all participants for HPV in the third trimester, marking a limitation. In addition, due to the rare nature of several HPV genotypes, they were unable to conduct a genotype-specific analysis in the current study.

“The fact that HPV was detected in 3.9% of biopsies performed under the membrane of the fetal side of the placenta suggests that although infrequent, true placental infection is possible,” authors concluded.

“Follow-up data through 5 years will be crucial in confirming if the HPV found in newborns has been cleared or if some virus remained undetected in basal cells and can reactivate later in childhood,” they wrote.

Referenceas

1. Khayargoli P, Niyibizi J, Mayrand MH, et al. Human Papillomavirus transmission and persistence in pregnant women and neonates. JAMA Pediatr. Published online May 22, 2023. doi:10.1001/jamapediatrics.2023.1283

2. Having a baby after age 35: how aging affects fertility and pregnancy. American College of Obstetricians and Gynecologists. Updated February 2023. Accessed July 14, 2023. https://www.acog.org/womens-health/faqs/having-a-baby-after-age-35-how-aging-affects-fertility-and-pregnancy#:~:text=A%20woman's%20peak%20reproductive%20years,you%20reach%20your%20mid%2D30s