The herpes simplex viruses HSV-1 and HSV-2 are a highly contagious and increasingly-common group of viral infections.  They are responsible for cold sores and genital herpes, and are caused respectively by herpes zoster.  In the general population, HSV symptoms range widely from none or very mild to severe, but these viral conditions are especially dangerous when they occur for the first time during pregnancy or in the immediate postpartum period.  When we discuss herpes infection in pregnancy, it is often as part of a larger group of infectious agents known as TORCH viruses or TORCH infections, and when these infections occur in the unborn or newly-born baby, they can result in severe morbidity or even death.  TORCH stands for:

• • T: toxoplasmosis 

• • O: Others,  specifically hepatitis B, HIV, syphilis, parvovirus, and varicella zoster (chicken pox) 

• • R: rubella

• • C: cytomegalovirus (CMV)

• • H: herpes simplex virus (HSV)

The structure of community-based midwifery care often includes longer appointments where fostering mutual respect and trust between the midwife and client is paramount.  Because of this, midwives have a unique opportunity to assess individual risk and provide education with regards to treating and preventing transmission of HSV-1 and HSV-2 both during pregnancy and in the postpartum time.

Herpes Simplex Viruses: An Overview

As mentioned above, there are two types of herpes simplex viruses.  HSV-1 is found in the trigeminal ganglia (a cluster of nerves found on both sides of the face) and is the primary virus that causes orofacial lesions, commonly known as “cold sores” or “fever blisters,” however it can also cause genital lesions.  HSV-2 is found in the lumbosacral ganglia (nerves of the lower spine and tailbone) and causes genital herpes infection.  According to Johns Hopkins Medicine, one in six adults suffer from genital herpes caused by either HSV-1 or HSV-2, and 50% to 80% of American adults have oral herpes caused by HSV-1 infection.  Both HSV-1 and HSV-2 can cause neonatal herpes infection during pregnancy or after birth, and this risk is increased when it results from a primary maternal infection during the third trimester or postpartum.

Neonatal Herpes Infection

The incidence of neonatal herpes worldwide is approximately 10 cases/100,000 live births or roughly 14,000 cases annually.  The majority of those infections are caused by HSV-2 (10,000).  While these infections are considered rare, they have the potential to be devastating.  Without treatment, the mortality rate is around 60% and even with antiviral treatment, death and long-term neurological impairment are common outcomes.  The biggest identified risk factors are premature rupture of membranes (PROM) and primary maternal infection in the third trimester.  The latter is the result of insufficient time for antibody development in the client and, therefore, in the baby.  In fact, 85% of all neonatal HSV infections are due to exposure during vaginal delivery; 50% are caused by a primary maternal HSV infection whereas less than 3% are the result of a recurrent maternal infection, and the majority of these neonatal cases (70%) come from exposure to asymptomatic genital infection near or during delivery.   Because of this, emphasis on prevention and early identification of potential infection are crucial in reducing neonatal transmission prenatally.

Management recommendations for herpes infection during the third trimester or at birth vary depending on whether it is a primary or recurrent infection.  If a primary infection is acquired during the third trimester, most guidelines recommend cesarean birth, particularly if the infection manifests in the 4 to 6 weeks preceding delivery.  Acquisition prior to this time could allow for adequate development of maternal antibodies.  In the latter scenario, if two consecutive vaginal cultures are negative and there are no active lesions at the time of delivery, a vaginal birth is a reasonable option as the baby should have sufficient maternal antibody protection.  However, in the event that birth is imminent and a vaginal birth occurs anyway, initiation of maternal and neonatal intravenous acyclovir as soon as possible is recommended due to the high risk of vertical transmission (41%).  In a client who has previously had a primary infection and has circulating antibodies, the likelihood of fetal HSV infection is low; if genital lesions are present at birth, the risk is approximately 2% to 5%.  An asymptomatic client with periodic viral recurrence has an even lower risk of passing the infection to her baby, roughly 0.02% to 0.05%. 

So, to summarize, the following clients would be reasonable candidates for vaginal birth (in order of risk):

• • The client with a primary infection prior to 34 to 40 weeks gestation who has two negative vaginal cultures and absent genital lesions at delivery.

• • The client with periodic recurrent infection with genital lesions present at birth.

• • The client with periodic recurrent infection who is asymptomatic and has no genital lesions present at birth. 

Below is a table depicting the recommended antiviral medications and their doses for treatment of herpes simplex during pregnancy:

Source:Straface, G., et al. Herpes Simplex Virus Infection in Pregnancy. Infectious Diseases in Obstetrics and Gynecology, 2012 

Abstinence from sexual intercourse or receptive oral sex during times of herpes outbreak recurrence in the non-pregnant partner, particularly during the third trimester, is the most protective option in preventing genital herpes in a non-infected client.  Barrier methods should be recommended throughout pregnancy during times the partner has no active lesions.  

However, 10% of neonatal herpes infections result from postpartum exposure to HSV-1 in caregivers, so additional education should be provided after birth regarding continued postpartum risk.

Risk of Neonatal Herpes Transmission During The Postpartum Period

Once a baby has been born, the risk of neonatal herpes infection doesn’t simply go away.  The reason newborns are at high-risk for serious complications and even death following transmission is essentially the same as the reason they are at-risk in utero: they have no antibodies to the herpes simplex viruses and are therefore more susceptible to developing serious illness.  Symptoms include lesions on their skin or in their eyes and mouth, HSV encephalitis, or disseminated (system-wide) HSV with associated multiorgan dysfunction and an 80% mortality rate if left untreated.  

Unlike babies who contract HSV during delivery due to contact with vaginal mucosa, newborns who contract the virus do so typically through contact with an active cold sore, lesions on the hands or fingers (called “herpetic whitlow”), and even through nursing if there is an active lesion present on the nipple or breast/chest.  So the important question is: how do we educate parents, families, friends, and care providers (including other midwives) about the importance of diligence?  The approach to this is two-fold and involves both prevention and early attention to signs and symptoms of illness.

 Prevention

• • Advise parents not to feed their baby from a breast/side of chest with active lesions noted, and to seek evaluation and treatment immediately.

• • Advise parents that no one with active lesions should have direct contact with their newborn- the provider should be gloved.  This includes non-family caregivers such as nurses and midwives who may have skin lesions or cold sores present.  

• • Provide education regarding the importance of good hand hygiene and practice this diligently yourself. Hands should be washed thoroughly with soap and water for at least 20 seconds prior to providing any care.  If a parent has active lesions and must have direct contact with their newborn, they should wash their hands every time they come home, prior to touching their baby, and before changing diapers.  Whenever possible, lesions should be well-covered.

• • Advise parents to ask family and visitors to refrain from kissing their baby.  Parents with active cold sores should not kiss their baby until these lesions have fully healed.

• • Remember the THANKS acronym when caring for newborns and use it to educate parents on the best ways to keep their baby safe from herpes infection as well as other illnesses:

Source: The Kit Tarka Foundation

Signs and Symptoms of Potential Infection

• Lethargy or irritability
• Abnormal cry (high-pitched, inconsolable, etc.)
• Poor feeding
• Abnormal temperature, either very high or very low
• Poor muscle tone (i.e. baby is limp or “floppy”)
• Respiratory distress, such as very rapid or very slow breathing, grunting, or retractions (“sucking in” of the skin below or between the ribs or above the collarbones)
• Skin rash or lesions of the eyes or oral mucosa

Conclusion

Midwives provide care not just for the pregnant client and their baby, but also frequently for the client’s whole family.  We fill a unique role in community practice whose vantage point allows us the opportunity to safeguard the current and future health of generations through education, counseling, and prevention.  By understanding the various ways a virus like herpes simplex can be transmitted and how its effects are dangerously amplified in the unborn and newborn baby, we can make a meaningful difference in reducing the frequency and severity of these infections.  

References

(n.d.). Kit Tarka Foundation: Preventing newborn baby deaths | United Kingdom. Retrieved June 19, 2023, from https://www.kittarkafoundation.org/

Herpes: HSV-1 and HSV-2. (n.d.). Johns Hopkins Medicine. Retrieved June 21, 2023, from https://www.hopkinsmedicine.org/health/conditions-and-diseases/herpes-hsv1-and-hsv2

Looker, PH.D, K. J., Margaret, PH.D, A. S., May PH.D, M. T., Turner, PH.D, K., Vickerman, PH.D, P., Newman, M.D., L. M., & Gottlieb, MD, S. L. (2017, January 31). First estimates of the global and regional incidence of neonatal herpes infection. The Lancet Global Health, 5(3), 300-309. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5837040/

Rudnik, M.D., PhD, C. M., & Hoekzma, M.D., G. S. (2002). Neonatal Herpes Simplex Virus Infections. 6. https://www.aafp.org/pubs/afp/issues/2002/0315/p1138.html#:~:text=Neonatal%20herpes%20simplex%20virus%20(HSV,3%2C000%20to%2020%2C000%20live%20births.

Straface, G., Selmin, A., Zanardo, V., De Santis, M., Ercoli, A., & Scambia, G. (2012, April 11). Herpes Simplex Virus Infection in Pregnancy. Infectious Diseases in Obstetrics and Gynecology, 2012(Special Issue: The Infections of Lower Genital Tract), 6. https://www.hindawi.com/journals/idog/2012/385697/