What Happens If I Have Genital Herpes During Labor?

If you have a history of genital herpes, it is completely normal to worry about passing the virus to your baby. The most important thing to know is that if you do not have an active outbreak or prodromal symptoms (early warning signs like tingling, burning, or nerve pain) when you go into labor, a vaginal delivery is generally considered very low risk, though the risk is never truly zero. Routine viral swab testing of an asymptomatic mother during labor is not recommended ^[1][2]. However, you must disclose your history to your care team so they can examine you for sores and ask about symptoms when labor begins.

If you do experience an outbreak or prodromal symptoms when your water breaks or labor begins, contact your obstetric team immediately. Do not wait for a visible sore to develop or resolve.

What Happens if You Have an Outbreak During Labor?

When active herpes sores or early warning symptoms are present at the onset of labor, the American College of Obstetricians and Gynecologists (ACOG) strongly recommends a Cesarean delivery (C-section) ^[3][1].

A C-section prevents the baby from passing through the birth canal. While this substantially lowers the risk of the baby being exposed to the virus, it does not completely eliminate it, especially if your water broke before the surgery ^[3][4].

Additionally, your care team will avoid invasive procedures that could create tiny cuts on the baby’s skin, making it easier for the virus to enter. This means avoiding tools like fetal scalp monitors, vacuums, or forceps, unless they are absolutely medically necessary ^[1][5].

Understanding the Risk to Your Baby

The risk of transmitting the herpes simplex virus (HSV) to your baby depends heavily on whether this is a new infection or an established, recurring one:

• Recurrent Outbreaks (Low Risk): If you had genital herpes before you got pregnant, your body has built up antibodies (protective proteins) against the virus. You pass these to your baby through the placenta. If you have a recurrent outbreak during labor, the transmission risk to your baby is about 1% ^[6][7].
• Primary (First-Time) Infections (High Risk): The highest risk occurs if you contract genital herpes for the very first time late in your pregnancy (third trimester). Because your body hasn’t had time to build and share antibodies with the baby, the transmission risk during a vaginal delivery is approximately 25% to 44% ^[7][8].
• Note on “First Outbreaks”: A first recognized outbreak is not always a true primary infection; sometimes it is a recurrence of an older, silent infection. Doctors can use blood tests and swab cultures to determine if the infection is truly new ^[8][9].

What to Expect After Your Baby is Born

If you had an active outbreak or history of HSV when you delivered, your baby’s pediatric team or neonatologist (a newborn intensive care doctor) will follow American Academy of Pediatrics (AAP) guidelines to monitor and protect them:

• Testing: If your baby was exposed to active lesions, they will usually be tested using a PCR swab (a laboratory test that detects viral genetic material) taken from their eyes, nose, and mouth. This is typically done around 24 hours after birth. Testing at 24 hours ensures that a positive result reflects true viral replication rather than just temporary contamination from the birth process ^[2][10].
• Observation vs. Treatment: The care plan depends on your infection type and the baby’s health. If your outbreak was a confirmed recurrence and the baby looks completely healthy, the medical team will likely observe them closely and wait for test results ^[8][11]. However, if it was a true primary (new) infection, or if the baby shows any signs of illness, the team will run additional tests (like blood and spinal fluid) and immediately start intravenous (IV) antiviral medication (acyclovir) ^[10][2].

Going Home: Warning Signs and Breastfeeding

Watch for Urgent Warning Signs: Neonatal HSV is a medical emergency and can occur without visible skin blisters. After going home, seek urgent medical assessment if your baby develops a fever or abnormal body temperature, extreme sleepiness (lethargy), irritability, poor feeding, breathing difficulties, seizures, or a vesicular rash (blisters) ^[10][12].

Breastfeeding Safety: You can safely breastfeed your baby, even during an outbreak, as long as there are no herpes lesions on your breasts or nipples ^[10][13]. If you have a lesion on one breast, do not feed or give expressed milk from that breast until it is completely healed. Keep lesions elsewhere on your body securely covered, and wash your hands thoroughly before touching your baby. Never kiss your baby if you have an active oral cold sore ^[10][14].

Preventing Outbreaks Before Labor

To lower the chances of having an outbreak when labor begins, obstetricians generally offer daily suppressive antiviral medication (like acyclovir or valacyclovir) starting around 36 weeks of pregnancy and continuing until delivery ^[15][16]. This medication is considered safe for the baby. It reduces viral shedding (when the virus is present on the skin without symptoms) and significantly lowers the chance of needing a C-section, though it does not guarantee that shedding or an outbreak won’t happen ^[3][15].