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.