The presence of Herpes Simplex Virus (HSV) does not automatically preclude a vaginal delivery, which is often referred to as a “natural birth.” For a pregnant person with a history of genital herpes, the possibility of delivering vaginally depends entirely on the clinical status of the infection at the time labor begins. The primary medical goal is to prevent the transmission of the virus to the newborn, which necessitates careful management and assessment leading up to and during the delivery.
Understanding the Risk of Transmission
The central concern with HSV during childbirth is the risk of vertical transmission, where the baby acquires the infection as it passes through the birth canal. This transmission can lead to neonatal herpes, a serious condition that can affect the skin, eyes, and mouth. It can also progress to involve the central nervous system, leading to brain swelling, or cause disseminated disease that affects multiple major organs.
The risk of transmission depends heavily on the timing and type of the maternal infection. A primary, or first-time, genital HSV infection acquired late in pregnancy presents the highest risk of transmission, estimated to be as high as 30 to 50% for the newborn. This high risk exists because the mother has not yet developed protective antibodies, which would normally cross the placenta to provide immunity to the fetus.
Conversely, a recurrent infection, where the mother has a history of the virus and circulating antibodies, carries a much lower risk, typically less than 3% for the infant. Neonatal infection is associated with significant morbidity and mortality, even with treatment. Therefore, medical management focuses intensely on reducing the likelihood of the baby being exposed to the virus during birth.
Antiviral Therapy During Late Pregnancy
Preventative measures are typically initiated in the third trimester to reduce the risk of a herpes outbreak occurring at the time of delivery. Suppressive antiviral therapy is usually recommended for pregnant individuals with a history of recurrent genital herpes. This therapy is commonly started at or around 36 weeks of gestation and continues until the time of delivery.
The purpose of this late-pregnancy treatment is to minimize the chances of a recurrence or asymptomatic shedding of the virus when labor begins. Medications such as acyclovir or its prodrug, valacyclovir, are commonly used for this suppressive regimen. Studies have demonstrated that this prophylactic treatment significantly reduces the rate of recurrence at delivery and the need for a Cesarean section due to an active outbreak.
The use of these antiviral medications during pregnancy is considered safe. By reducing the amount of virus present in the genital tract, this therapy increases the likelihood of a safe vaginal delivery. This preventative strategy is an important component of the overall management plan for pregnant persons with a history of the infection.
Determining the Delivery Method
The decision to proceed with a vaginal delivery is based on a thorough clinical assessment performed when labor begins or when the membranes rupture. A vaginal birth is generally considered safe if the mother has no signs of an active genital herpes outbreak at the time of delivery. This means there should be no visible lesions, blisters, or ulcers on the external genitalia, cervix, or surrounding areas.
If a person has active genital lesions or is experiencing prodromal symptoms, such as vulvar pain, itching, or burning, a Cesarean section is typically recommended. The presence of these symptoms or lesions suggests active viral shedding, which increases the baby’s risk of exposure during passage through the birth canal. The Cesarean delivery is performed to prevent the baby’s skin and mucous membranes from coming into direct contact with the virus.
For women with a history of recurrent herpes, the presence of visible lesions still prompts the recommendation for a Cesarean section. If the membranes have been ruptured for an extended period, the benefit of a Cesarean section may be less clear, and the decision is made on a case-by-case basis considering the duration of rupture and the presence of lesions.
The highest-risk scenario is a primary HSV infection acquired late in the third trimester or near delivery, where a Cesarean section is strongly recommended even if the infection is not clinically apparent at the time of birth. In all cases, the decision about the delivery method is a collaborative one between the patient and the healthcare team, prioritizing the prevention of neonatal infection.
Care and Monitoring After Birth
Careful monitoring of the newborn is standard practice for all babies born to mothers with a history of genital herpes, regardless of the delivery method. This is especially true if the mother had a known recurrence or active lesions at the time of birth. For asymptomatic infants exposed to the virus, surveillance may include obtaining viral cultures or Polymerase Chain Reaction (PCR) swabs from the baby’s mouth, nose, eyes, and rectum approximately 24 hours after birth to check for viral exposure.
If the mother had active lesions or a primary infection at delivery, the baby is closely observed for signs of infection, such as lethargy, poor feeding, or a vesicular rash. In high-risk situations, such as primary maternal infection, some experts recommend starting the baby on intravenous antiviral therapy, such as acyclovir, immediately, even before the culture results are finalized. This prompt action is taken because early treatment is vital to improving outcomes for an infected infant.
Meticulous hand hygiene is necessary for mothers with active lesions to prevent postnatal transmission. Mothers with an active cold sore (oral herpes) should avoid kissing or nuzzling the baby until the lesion has crusted over. Breastfeeding is generally safe unless there are active herpetic lesions directly on the breast, requiring a temporary alternative feeding method and covering any other skin lesions.