Human papillomavirus infects placental trophoblast and Hofbauer cells, but appears not to play a causal role in miscarriage and preterm labor

INTRODUCTION: Recently, an association between human papillomavirus (HPV) infection and both spontaneous abortion and spontaneous preterm delivery was suggested. However, the reported HPV prevalence in pregnant women varies considerably and reliable conclusions are difficult. We aimed to investigate HPV infection in placental tissue of a Danish study cohort. Furthermore, we studied the cellular localization of HPV.

MATERIAL AND METHODS: In this prospective case-control study, placental tissue was analyzed for HPV infection by nested PCR in the following four study groups: full-term delivery (n=103), spontaneous preterm delivery (n=69), elective abortion (n=54), and spontaneous abortion (n=44). Moreover, HPV cellular target was identified by the use of in situ hybridization.

RESULTS: HPV prevalence in placental tissue was 8.7% in full-term deliveries, 8.8% in spontaneous preterm deliveries, 10.9% in spontaneous abortions, and 20.4% in elective abortions. 12 different HPV-types were detected and placental HPV infection was associated to a disease history of cervical cancer. HPV DNA was identified in trophoblast cells, cells of the placental villi mesenchyme including Hofbauer cells, and in parts of the encasing endometrium.

CONCLUSION: We conclude that placental HPV infections are not likely to constitute a risk factor for spontaneous preterm labor or spontaneous abortions in the Danish population, although an effect of HPV DNA in placental cells cannot be excluded. This article is protected by copyright. All rights reserved.