Associações da infecção pelo HPV e da histopatologia placentária com o parto prematuro

Abstract

Preterm birth occurs up to 36 weeks and 6 days of gestational age, excluding the period considered as miscarriage. Among its causes, premature rupture of the ovular membranes accounts for one third of cases of prematurity and may be associated with the presence of inflammatory/infectious processes in the placenta, such as those resulting from bacterial and viral infections. Human papillomavirus (HPV) infection is the most common viral infection of the female genital tract, and in vitro studies and in animal models consider HPV as an agent of adverse events during pregnancy. However, the results of clinical studies are controversial regarding the association between HPV and preterm birth. Therefore, this study aims to analyze possible associations between placental HPV infection and placental histopathological alterations with preterm birth. For this purpose, an observational and cross-sectional study of 41 pregnant women was carried out, with emphasis on the anatomopathological analysis of the placentas and the molecular detection of HPV by Real-Time Polymerase Chain Reaction (qPCR) of vaginal secretion. In this study, a prevalence of HPV infection of 18.92% was identified, with a higher relative rate (33.33%) associated with spontaneous preterm birth, with a predominance of HPV types non-16 and non-18 and with a higher prevalence of infection in older women compared to younger women (p-value = 0.006). However, no statistically significant association of HPV with preterm birth was observed. Higher proportions and risks of occurrence of placental inflammatory changes (chorioamnionitis and vasculitis) were observed in placentas from spontaneous preterm birth when compared to induced preterm (OR = 48) and full-term (OR = 17.33) births. Thus, the present study allows us to conclude that maternal HPV infection is not associated with preterm birth, despite the higher relative prevalence in pregnant women with spontaneous preterm birth, and that placental inflammatory histopathological alterations considerably increase the risk of spontaneous preterm birth. Complementary studies aiming at the analysis of microbiota and inflammatory biomarkers in the vaginal cavity and placenta may guide future clinical research for the prediction of preterm birth.