Maternal–Fetal Implications of Herpes Virus Infection: An Updated Review

Herpes simplex virus (HSV) infection is highly prevalent worldwide and poses important risks during pregnancy due to the potential for vertical transmission and severe neonatal disease. HSV-1 is traditionally associated with orofacial lesions and HSV-2 with genital infection; however, HSV-1 has emerged as a significant cause of genital and neonatal herpes. Physiological immunomodulation during pregnancy may facilitate viral reactivation and replication. Vertical transmission may occur intrauterinely, intrapartum, or postnatally, with approximately 85% of neonatal infections acquired during delivery through contact with infected genital secretions. The risk is highest when primary maternal infection occurs in the third trimester, before adequate transplacental transfer of protective antibodies. Neonatal infection may present as disease limited to the skin, eyes, and mouth; central nervous system involvement; or disseminated multiorgan disease, the latter associated with high morbidity and mortality. Maternal infection ranges from asymptomatic viral shedding to painful vesiculoulcerative lesions and, rarely, disseminated disease. Because asymptomatic shedding is common, diagnosis relies on laboratory confirmation using polymerase chain reaction (PCR) or viral culture, with type-specific serology aiding in distinguishing primary from recurrent infection. Management aims to reduce symptoms, viral shedding, recurrences near delivery, and vertical transmission. Acyclovir and valacyclovir are safe and effective in pregnancy. Suppressive therapy from 36 weeks' gestation reduces recurrences and viral shedding at delivery and decreases the need for cesarean delivery, which is recommended when active lesions or prodromal symptoms are present at labor. Neonatal herpes requires prompt recognition and intravenous acyclovir therapy to reduce mortality and neurological sequelae. Preventive strategies include counseling, behavioral risk reduction, suppressive antiviral therapy, and avoidance of neonatal exposure to active lesions.