To evaluate the role of placental human papilloma virus (HPV) infection as a risk factor for spontaneous preterm birth: a prospective case control study

Objectives i) To compare the placental human papilloma virus (HPV) deoxynucleic acid (DNA) status of preterm deliveries with full term deliveries and to identify high risk (HR) genotypes (HPV 16 and 18); and ii) To compare the perinatal outcomes of HPV positive with HPV negative pregnant women. Methods A case control study was carried out on 100 antenatal women with singleton live pregnancies admitted in labor ward of a tertiary care teaching hospital from April 2017 to March 2018. The two study groups were i) spontaneous preterm deliveries between 24 and 36 + 6 weeks (n=50) and ii) full term deliveries >= 37 weeks (n=50). The placental tissue was analysed for HPV DNA and HR HPV genotypes were detected by type specific primers. A comparative analysis of perinatal outcomes between HPV positive and negative women was done. Results An overall placental tissue HPV prevalence of 12% (12/100) was observed in study cohort which was not significantly different between preterm and full term deliveries (16 vs. 8%, p=0.218). HPV 16 was significantly associated with preterm births (p=0.04). Both HPV affected and non-affected women were comparable in terms of mode of delivery and neonatal outcomes. However, a statistically significant association of preterm neonatal intensive care admissions with HR HPV 16 genotype was observed (p=0.04). Conclusions Spontaneous preterm births can be attributed to placental HPV infection, specifically HR HPV 16 genotype. This association identifies a potentially preventable cause of prematurity and its associated complications, in wake of availability of an effective vaccine.