HPV infection among pregnant women common, but vertical transmission infrequent

Vaginal human papillomavirus (HPV) is frequently detected among pregnant women, but perinatal transmission does not appear to occur as often, according to data from the HERITAGE* study.

HERITAGE included 1,050 pregnant women (mean age 31.3 years) at no more than 14 weeks of gestation. HPV DNA testing was performed on self-collected vaginal samples (during pregnancy) and placental samples (swabs and biopsies after birth). Testing (birth, 3 months, and 6 months) was also done on conjunctival, oral, pharyngeal, and genital samples collected from children of mothers positive for HPV.

HPV prevalence among pregnant women at baseline was 40.3 percent (95 percent confidence interval [CI], 37.3–43.3). Of the 422 HPV-positive women, 280 (66.4 percent) had at least one high-risk genotype and 190 (45.0 percent) were coinfected with multiple genotypes.

HPV was detected in 92 of 860 placentas (10.7 percent, 95 percent CI, 8.8–12.9) overall, but only 14 of 361 (3.9 percent) of biopsy specimens on the foetal side under the amniotic membrane were positive.

The rate of neonatal HPV at birth and/or at 3 months was 7.2 percent (95 percent CI, 5.0–10.3) overall, with the conjunctiva being the most frequent site of infection (3.2 percent, 95 percent CI, 1.8–5.6). This was followed by the mouth (2.9 percent, 95 percent CI, 1.6–5.2), the genital area (2.7 percent, 95 percent CI, 1.4–4.9), and the pharynx (0.8 percent, 95 percent CI, 0.2–2.5).

Of note, all HPV detected in children at birth cleared before the age of 6 months.

*The Human Papillomavirus Perinatal Transmission and Risk of HPV Persistence Among Children