Nipah virus and pregnancy: a comprehensive review of risks, clinical management, and prevention

Nipah virus (NiV) is a highly pathogenic zoonotic paramyxovirus first identified in Malaysia during 1998–1999. The World Health Organization (WHO) has classified NiV as a priority pathogen, citing its high case fatality rate (40%-90%), documented person-to-person transmission, and the absence of licensed vaccines or therapeutics. The virus spreads from fruit bats ( Pteropus spp.) to humans via contaminated food, most notably raw date palm sap in Bangladesh and India, and through close contact with infected individuals, particularly in healthcare settings. Clinical illness ranges from asymptomatic infection to severe encephalitis and acute respiratory distress syndrome (ARDS). Pregnancy induces stage-specific immunological and cardiovascular adaptations that may alter the course of viral infection and complicate clinical management. Although the placenta was long considered an effective barrier, experimental studies have demonstrated NiV replication in placental and fetal tissues, and a 2020 case from Bangladesh documented transplacental transfer of high titers of maternal anti-NiV IgG to the neonate. That finding indicates prior maternal exposure and the passive acquisition of humoral immunity by the neonate; it does not constitute confirmed vertical transmission, which would require direct virological evidence in fetal or neonatal specimens. Given the severe consequences of other viral infections during pregnancy (e.g., SARS-CoV-2, Ebola), understanding NiV's clinical behavior in pregnancy, its capacity for mother-to-child transmission, and its impact on fetal and neonatal outcomes is an urgent research priority. This review synthesizes evidence from human case reports, surveillance data, and animal studies to provide a comprehensive analysis of NiV infection in pregnancy, covering virology and the natural reservoir cycle, human spillover and epidemiology, clinical features and management, pregnancy-specific risks and vertical transmission, and research priorities for this high-risk population.