Neonatal Herpes Encephalitis

Herpes simplex virus (HSV) infection is extremely common in adults, including pregnant women. If a pregnant woman has genital herpes, her baby is also at risk for infection. Fortunately, the mother’s medical team can usually prevent transmission of HSV from mother to baby. This includes screenings for maternal HSV and appropriate management of pregnancies involving HSV (which may include a C-section delivery and/or antiviral therapy). Failure to take the necessary precautions to prevent neonatal herpes is negligence and can have devastating effects on the baby, including neonatal herpes encephalitis, which can result in permanent brain damage (1).

Neonatal Herpes Encephalitis - HSV

Jump to:

Types of herpes simplex virus (HSV)

Between 2015 and 2016, about 47.8% of adults in the U.S. were infected with HSV type 1 (HSV-1), and 11.9% had HSV type 2 (HSV-2). Some people experience painful blisters or sores caused by herpes, but often, this infection is asymptomatic (2). Both HSV-1 and HSV-2 can pose a severe danger to neonates when transmitted during delivery.

Causes of neonatal herpes encephalitis

Most neonatal infections result from exposure to HSV in the mother’s genital tract during birth, although occasionally the baby may become infected earlier in pregnancy or after birth.

If a mother has primary (initial/first-time) genital HSV infection and is shedding the virus (i.e., the virus has successfully reproduced in a host cell and is spreading) late in pregnancy, she is 10-30 times more likely than a woman with a recurrent infection to transmit the virus to her baby (1).

Risk factors for neonatal herpes encephalitis

Risk factors for neonatal HSV include the following (3, 4):

  • First-time maternal infection in the third trimester
  • The mother lacks HSV antibodies
  • Use of invasive instruments, such as fetal-scalp electrode monitoring or forceps and vacuum extractors
  • Delivery before 38 weeks
  • Maternal age less than 21 years
  • HSV has spread to the mother’s cervix (as opposed to only her vulva)

Signs and symptoms of neonatal herpes

Neonatal herpes manifests itself in three main forms (5):  

  • Localized skin, eyes, or mouth (SEM) herpes
  • Encephalitis: affecting the brain, with or without involvement of the skin, eyes, or mouth
  • Disseminated herpes infection: affecting multiple parts of the body, including the brain (encephalitis), lungs, liver, adrenals, skin, eye, or mouth

Signs of neonatal herpes typically present between six and 21 days after the baby is delivered.  The following are a few signs doctors should look for (6, 7):

  • Blisters (although these are stereotypically associated with HSV, it is important to note that many infants with HSV do not develop lesions)
  • Irritability
  • Lethargy
  • Respiratory problems (e.g. grunting, rapid breathing, apnea)
  • Feeding problems
  • Cyanosis (blue appearance)
  • Jaundice
  • Bleeding easily
  • Fever
  • Bulging fontanel
  • Abnormal movements/positioning
  • Seizures (if a baby exhibits seizures without an obvious underlying cause, neonatal herpes encephalitis should always be considered)
  • Hepatitis
  • Pneumonitis
  • Disseminated intravascular coagulation (DIC)

Sometimes, the signs of neonatal herpes infection go unnoticed or are misattributed to another condition, such as bacterial sepsis. Failure to promptly diagnose neonatal herpes greatly increases the seriousness of the disease and increases the chance of herpes encephalitis, permanent brain damage, and death. Neonatal herpes that is localized in the skin, eyes, or mouth is unlikely to cause permanent harm, but without prompt treatment, it may progress to the central nervous system (encephalitis) or into a disseminated disease pattern, both of which are extremely dangerous (7).  

Diagnosis of neonatal herpes

A neonatal diagnosis is determined by the following (6, 8):

  • Skin culture (if the baby has a blister, medical professionals will remove a small sample of it)
  • Blood or plasma test
  • Swab culture (from the nose, throat, or rectum)
  • Urine test
  • CT scan or MRI scan
  • Lumbar puncture for cerebral spinal fluid (CSF)
  • Additional testing

Treatment for neonatal herpes

All babies with suspected or diagnosed HSV must be treated immediately with intravenous (IV) acyclovir (Zovirax). Prompt treatment is crucial, especially in cases of disseminated infections. SEM HSV infections are treated for at least 14 days, whereas encephalitis or DIS infections require at least 21 days of therapy. If HSV has infected the baby’s eyes, they should also be given a topical ophthalmic solution and be seen by an ophthalmologist. Infants should also be treated for any related complications, such as seizures.

Following the initial acyclovir therapy, infants may need additional oral acyclovir suppressive therapy for six months. If the eye is affected, they may require this for longer (up to one ear).

When treated promptly, babies with  HSV have very good outcomes. Before antiviral therapy was widely administered, neonates with herpes encephalitis had a one-year mortality rate of 50%. Now, it has dropped to 4%. Likewise, the mortality rate for disseminated disease has gone from 85% to 29%. Antiviral treatment has also improved outcomes for surviving neonates with disseminated herpes; the proportion with normal neurological development has increased from 50% to 80%.

Preventing neonatal herpes: reducing transmission of HSV infection

Identification of pregnant women who have (or are at risk of having) HSV is a critical component of preventing transmission to a baby. If medical professionals suspect that a pregnant patient is infected with HSV, they should recommend viral or serologic testing, to determine if she carries the infection or is producing HSV antibodies (which also provides evidence of infection). Current recommendations of the American College of Obstetricians and Gynecologists (ACOG) do not include routine HSV screening, but patients can ask to be tested if they believe they may be at risk (10).  

The most effective measure to prevent perinatal herpes infections is to avoid viral exposure to the baby when primary genital herpes develops in late pregnancy (because the mother has not yet developed antibodies to fight the infection, and it is likely that the virus will be active in the birth canal during delivery). If a pregnant woman’s partner has herpes, it is also especially important to avoid transmitting it to her during the third trimester. Doctors should recommend the use of condoms and other forms of contraception that help to prevent transmission. If the expectant mother’s partner has an outbreak, it is wise to abstain from sex entirely until the baby is born — it is important to know that condoms are not 100% effective in preventing transmission of herpes or other STDs (11).

If a woman has a primary HSV outbreak during pregnancy (or active recurrent HSV), her doctor may give her oral antiviral treatment (such as acyclovir, famciclovir, or valacyclovir) to reduce the duration and severity of symptoms and viral shedding. If a woman has a severe infection, she may benefit from intravenous acyclovir.

ACOG recommends Cesarean delivery (C-section) to prevent HSV transmission to the baby if the mother has active genital lesions or prodromal symptoms (that is, if it appears to be a new infection). If lesions are only found on nongenital areas, vaginal delivery may be possible (10). Treatment with acyclovir can reduce the need for Cesarean delivery.

If a woman with herpes delivers vaginally, there are several precautions that should be taken. Unless absolutely necessary, medical professionals should avoid the following:

  • Invasive monitoring techniques such as fetal scalp electrodes
  • Use of delivery instruments (forceps and vacuum extractors)
  • Artificially rupturing the fetal membranes (amniotomy)

Additionally, lesions near the genitals should be covered with an occlusive dressing.

Neonates born to women with active genital lesions, with a confirmed or suspected HSV infection should be:

  • Isolated and managed with contact precautions
  • Closely monitored
  • Immediately treated with IV acyclovir (5)

To prevent postnatal transmission of HSV to an infant, medical professionals should counsel family members with currently or recently active lesions to take precautions around the infant. For example, those with cold sores should avoid kissing the baby, and mothers who have herpes lesions on their breasts should also avoid breastfeeding until the lesions are resolved (9).

Neonatal herpes encephalitis and medical malpractice

Listed below are issues that may constitute negligence in pregnancy, delivery, and neonatal situations involving HSV:

  • Failure to diagnose HSV in a pregnant woman
  • Failure to timely diagnose and treat HSV in an infant
  • Failure to properly deliver the baby of an infected mother in order to avoid risks of infection in the baby. This includes failure to perform a C-section when indicated, as well as utilization of delivery instruments and other invasive tools, such as a fetal scalp electrode.
  • Failure of the physician to obtain adequate informed consent, which includes advising the mother of the risks and alternatives of delivery methods, such as vaginal birth versus C-section delivery.

It is crucial that the physician take a thorough history of the pregnant woman, and this includes asking about HSV infection and risk factors. If major risk factors for or signs of HSV are present, the physician should test the mother. If a mother has HSV, all measures must be taken – and standards of care followed – in order to prevent the spread of the infection to the baby. If the baby is at risk of infection, they must be monitored closely after delivery, and if any signs of HSV are present, the baby must be treated and tested for the infection. Failure to promptly treat an infant with HSV and failure to follow the standards of care listed above constitute negligence. If this negligence leads to injury in the baby, it is medical malpractice.

Damage caused by neonatal herpes is considered a birth injury. Birth injury cases require extensive knowledge of both malpractice law and medicine. For the best case outcomes, it’s critical to find an attorney and a firm that focus specifically on this area of law. Reiter & Walsh, P.C. was established to focus exclusively on birth injury cases. Our team is based in Michigan, but we handle cases throughout the United States. We give personal attention to each family we work with, and you pay nothing unless we win your case.Free Case Review | Available 24/7 | No Fee Until We Win

Free Case Review | Available 24/7 | No Fee Until We Win

Phone (toll-free): 888-419-2229
Press the Live Chat button on your browser
Complete Our Online Contact Form

Video: neonatal herpes encephalitis attorneys discuss birth injuries

Watch a video of attorneys Jesse Reiter and Rebecca Walsh discussing birth injuries.


  1. Kimberlin, D. W., Baley, J., & Committee on Infectious Diseases. (2013). Guidance on management of asymptomatic neonates born to women with active genital herpes lesions. Pediatrics, peds-2012.
  2. National Center for Health Statistics. (2018, February 07). Retrieved October 18, 2018, from
  3. Whitley, R. (2004). Neonatal herpes simplex virus infection. Current opinion in infectious diseases, 17(3), 243-246.
  4. (n.d.). Retrieved October 18, 2018, from
  5. Rudnick, Caroline M., and Grant S. Hoekzema. “Neonatal herpes simplex virus infections.” American Family Physician 65.6 (2002).
  6. Neonatal herpes simplex Symptoms & Causes | Boston Children’s Hospital. (n.d.). Retrieved October 18, 2018, from
  7. (n.d.). Retrieved October 18, 2018, from
  8. (n.d.). Retrieved October 18, 2018, from
  9. (n.d.). Retrieved October 18, 2018, from
  10. Horsley, L. (2008). ACOG releases guidelines on managing herpes in pregnancy.
  11. (n.d.). Retrieved October 18, 2018, from
  12. (n.d.). Retrieved October 18, 2018, from

The above information is meant only to be an educational resource. It is not meant to be, and should not be, interpreted as medical advice.