Herpes simplex virus (HSV) infection, while common, becomes a particular concern during pregnancy. Understanding the virus and its potential implications can help manage concerns and ensure the well-being of both the pregnant individual and the infant. While transmission to the baby is not always guaranteed, being informed about the risks and available management strategies is important to reduce complications.
Understanding Herpes and Transmission Pathways
Herpes is caused by the herpes simplex virus (HSV), which primarily exists as HSV-1 and HSV-2. HSV-1 is commonly associated with oral herpes (cold sores) but can also cause genital infections. HSV-2 is most frequently linked to genital herpes. Both types can be transmitted from a pregnant individual to their infant, though the method and risk of transmission vary.
Transmission can occur through three main pathways. In utero (congenital herpes) transmission, where the virus passes from the placenta to the fetus during pregnancy, is very rare (estimated at about 5% of neonatal HSV cases). Perinatal transmission, the most common pathway (accounting for approximately 85% of neonatal HSV infections), occurs when the infant is exposed to the virus as they pass through the birth canal during a vaginal delivery. Postnatal transmission happens after birth, typically through direct contact with an active herpes lesion from a caregiver.
The risk of transmission is highest if the pregnant individual acquires a primary genital herpes infection late in pregnancy, especially during the third trimester, because the body has not yet developed protective antibodies to pass to the baby.
Potential Impact on the Infant
Neonatal herpes is a serious infection with significant consequences for the infant. Its severity depends on whether the infection is localized or has spread. Untreated, it can lead to severe health issues, including permanent disability or death.
Neonatal herpes can manifest in three main forms. Skin, eye, and mouth (SEM) disease involves lesions on the skin, eyes, or inside the mouth. While SEM disease has the best prognosis, it can progress if left untreated. Central nervous system (CNS) disease affects the brain and spinal cord, often leading to encephalitis (brain inflammation). Symptoms can include seizures, lethargy, poor feeding, irritability, and temperature instability. Disseminated disease is the most severe form, affecting multiple organs like the liver, lungs, and adrenal glands, and often includes CNS involvement.
Even with treatment, infants with CNS or disseminated disease may experience long-term neurological problems, such as developmental delays, intellectual disability, cerebral palsy, and epilepsy. Early diagnosis and immediate antiviral treatment are essential for improving outcomes and reducing severe complications.
Medical Management During Pregnancy
Managing herpes during pregnancy involves proactive medical steps to reduce infant transmission. Healthcare providers discuss the individual’s herpes history and assess outbreak risk as pregnancy progresses. Open communication with the healthcare team is important for developing an appropriate management plan.
Antiviral medications play a significant role in preventing transmission. For individuals with recurrent genital herpes, suppressive antiviral therapy is often recommended from around 36 weeks of gestation until delivery. Acyclovir or valacyclovir are commonly prescribed. These medications reduce outbreak frequency and minimize viral shedding in the genital tract, lowering the risk of viral presence at delivery. Studies indicate these antivirals are considered safe during pregnancy and do not appear to increase birth defects.
Delivery Planning and Prevention
Careful delivery planning is essential to prevent neonatal herpes transmission by minimizing infant exposure to the virus during birth. The mode of delivery depends on the presence of active herpes lesions or symptoms at labor onset.
If active genital herpes lesions or prodromal symptoms (e.g., tingling or itching) are present when labor begins, a Cesarean section (C-section) is recommended. This surgical method avoids infant contact with lesions in the birth canal, the most common transmission route. If no active lesions or symptoms are present at labor onset, a vaginal delivery may be considered safe. While a C-section significantly reduces transmission risk, it does not completely eliminate it. Healthcare providers discuss these options and associated risks and benefits to make an informed delivery decision.