There are over 100 herpes viruses. HSV-1 and HSV-2 are common skin conditions and affect a considerable portion of the population. According to the World Health Organization, an estimated 3.7 billion people under age 50 have HSV-1, and 491 million people under 50 have HSV-2. In the United States, approximately 22% of pregnant women have HSV-2. Most of these mothers have the virus before getting pregnant, and 2% of expecting mothers will acquire HSV-1 or HSV-2 during their pregnancy. Other than an occasional outbreak, no long-term adverse health outcomes exist in adults with HSV. Only about 5–15% of infected individuals report symptoms.

An HSV infection in a newborn can be a severe condition with detrimental effects. The good news is that transmission rates during pregnancy and birth are low. Learn how the herpes simplex virus can affect you and your baby during pregnancy, what medications are safe to use, and how to prevent transmission to your baby. 

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There is a negative stigma attached to the herpes virus. People may joke about it or shame people for having herpes. There are over 100 herpesviruses, and of those, 8 affect humans. The varicella-zoster virus that causes chickenpox is also in this group. The two most common are the herpes simplex virus type 1 and type 2. HSV-1 and HSV-2 are common skin conditions, and you should not be ashamed or embarrassed if you have HSV. The truth is that this virus affects a considerable portion of the population and one in five women. If you do not have it, you likely have friends and family who do. 

Herpes Simplex Virus Types

Herpes Simplex Virus Type 1 is known as oral herpes. HSV-1 transmits from oral-to-oral contact and is typically the cause of cold sores. HSV-1 can also be transmitted through oral-genital contact to cause infection in or around the genital area. Herpes Simplex Virus Type 2 is frequently called genital herpes and is sexually transmitted. The infections caused by HSV-1 and HSV-2 are lifelong, and there is no cure. 

Signs and Symptoms 

Both types of herpes infections are mostly asymptomatic and may go unrecognized. According to the American College of Obstetricians and Gynecologists, only about 5–15% of infected individuals report symptoms. 85-95% are asymptomatic, meaning they have zero noticeable symptoms. The most common symptoms are blisters or ulcers, typically in the mouth or the genital area. These blisters can range from mild to severe in terms of pain. It is possible to see other symptoms before a blister appears, like fever, swollen lymph nodes, headache or body aches, pain when you urinate, or tingling or shooting pain in your hips, butt, or legs. In the scientific literature, the symptoms that occur before a blister are called prodromal symptoms.


According to the World Health Organization, an estimated 3.7 billion people under 50 have HSV-1. That is a total of 67% of the world’s population. The prevalence differs significantly among different countries, highest in Africa (88%) and lowest in the Americas (45%). 

HSV-2 is less common but still is found in an estimated 491 million people aged 15-49 worldwide. That amounts to about 13% of the global population. This virus also disproportionately affects women because sexual transmission is more efficient from men to women. As of 2016, the WHO estimated that 313 million women and 178 million men lived with the infection. Like HSV-1, the prevalence is higher in Africa (44% in women and 25% in men) and lower in the Americas (24% in women and 12% in men).

According to the American College of Obstetricians and Gynecologists, approximately 21% of women had serologic evidence of HSV-2 infection. A serologic test detects antibodies of a microorganism in your blood, and if you have been exposed to a microorganism, like HSV, antibodies would be present. ACOG notes that serologic studies of HSV-2 underestimate the prevalence of genital herpes because HSV-1 also causes genital disease. In addition, about 10% of women who are HSV-2 negative have positive partners. Which means they are at risk for transmission of HSV-2 during pregnancy. 


If you have had a previous outbreak from HSV-1 or HSV-2, you have likely been tested for the virus. Since this is a lifelong infection, there is no reason to undergo another test. Prenatal care providers do not routinely screen pregnant patients for HSV. If you have had any signs of HSV in the past and have not been tested, now would be a good time to request a test. You can test for HSV with a simple blood test.


The herpes simplex virus transmits from contact with infected skin surfaces, like the mouth or genitals. It spreads by contact with sores or fluids of someone infected with the virus. HSV-1 is mainly transmitted by oral-to-oral contact to cause oral herpes infection, and it can also be transferred to the genital area to cause genital herpes. HSV-2 is sexually transmitted. The likelihood of transmission of either type of virus is highest when there are active sores. However, if you are engaging in sexual activity or kissing someone infected, you could contract it, even if there are no visible signs of the virus. HSV doesn’t survive long outside of your body or off your skin, so the risk of contracting it from touching a surface is low. 

HSV and Pregnancy 

In the United States, approximately 22% of pregnant women have HSV-2. Most of these mothers have the virus before getting pregnant, and 2% of expecting mothers will acquire HSV-1 or HSV-2 during their pregnancy. According to the American College of Obstetricians and Gynecologists, about 75% of expecting mothers with HSV-2 can expect at least one recurrence during pregnancy. Also, about 14% will have prodromal symptoms or recurrence at birth. During your pregnancy, your immune system is suppressed, which could contribute to why an outbreak is more likely. 

Neonatal Herpes 

Other than an occasional outbreak or sore, no long-term adverse health outcomes exist in adults with HSV. An HSV infection in a newborn can be a more serious health concern. When a baby contracts HSV, it is primarily through contact at birth. Neonatal herpes is rare, and according to the World Health Organization, it occurs in an estimated 10 out of every 100,000 births globally. Symptoms could be present at birth but more frequently happen in the days and weeks following. The symptoms of HSV in a baby can range from lesions on the skin to organ failure. For more detailed information on how this virus presents in babies, this article is an excellent resource. Before the availability of antiviral drugs, the death rate for babies who contracted HSV was very high. The prognosis has dramatically improved with the use of antiviral medicines.

In-utero infection is rare and is estimated to occur in about 1 in 300,000 births in the United States. The outcomes can be severe and include neurological disabilities and problems with the development of the eyes. The American College of Obstetricians and Gynecologists states that although HSV has been associated with an increased risk of spontaneous abortion, recent studies do not support such a risk. 

Due to the severity of HSV infection in babies, the focus for someone with HSV should be on preventing transmission. 

Risks of Transmitting HSV to Your Baby 

If you have HSV, there is always the possibility of transferring the infection to your baby. That risk varies greatly depending on several factors. The good news is that most babies born to mothers with HSV do not contract the virus.

For women who contract HSV before becoming pregnant or early in their pregnancy, the risk of infection is about 1%. If you contract the virus later in your pregnancy, especially in the third trimester, the risk of passing it to your baby increases to 30%-50%. The risk is higher when you contract it in the third trimester because your body does not have enough time to develop antibodies. The virus levels in the genital tract are highest early in the infection.

There are some signs to keep an eye out for in your baby, including a low-grade fever, irritability, a skin rash that looks like pimples or blisters, or if your baby is not feeding well. Please disclose your HSV diagnosis to your pediatrician and bring up any questions about limiting the risks to your baby. 

If Your Partner Has HSV 

If your partner, or someone you are sexually active with, has HSV and you do not, you should be particularly careful when you are pregnant. Caution is essential in the third trimester. Even if your partner has no visible symptoms, use condoms throughout pregnancy. Remember that condoms are not 100% effective, but they can reduce the risk of transmission. If symptoms present, avoid oral and sexual intercourse, especially in your third trimester. Please talk to your doctor or midwife about the HSV status of your partner for their recommendations. 

Treatment and Antiviral Drugs 

There is no cure for HSV, and no vaccines are currently available. There are antiviral medications used to reduce the frequency and severity of symptoms. The three drugs are acyclovir, famciclovir, and valacyclovir. While we do have evidence for some of these, there are no studies on using famciclovir in pregnancy.

The drugs most commonly used for expecting mothers are acyclovir which goes by the brand names Sitavig and Zovirax, and valacyclovir goes by the brand name Valtrex. These drugs are similar in that valacyclovir is a prodrug of acyclovir. Valacyclovir is converted to acyclovir after it is metabolized in the liver. Both are considered safe to take during pregnancy from studies in animals and humans. If you have an outbreak during your pregnancy, you may get a prescription for these drugs. These antivirals are also used proactively in the weeks leading up to your birth to prevent an outbreak.

The CDC and ACOG recommended that expecting mothers with genital HSV start taking an antiviral at week 36 until birth. The goal is to avoid having an outbreak when you go into labor, which can increase the risk of passing HSV to your baby. 

Vaginal vs. Cesarean Birth 

While the instances of neonatal herpes are low, it is severe enough that cesarean birth is recommended when genital lesions or prodromal symptoms are present. The prodromal symptoms appear before an outbreak and include fever, swollen lymph nodes, headache or body aches, pain when urinating, or tingling or shooting pain in your hips, butt, or legs. If you have HSV from before you became pregnant and had no symptoms, you can still have a vaginal birth. If you contract HSV in the third trimester, your doctor may recommend a cesarean birth due to the risk of viral shedding, which tends to be higher early on in the infection.

According to a study that focused on women with HSV in genital secretions at birth, cesarean birth reduced the risk of transmission from mother to baby. 1.2% of infants born via cesarean contracted neonatal herpes compared with 7.7% of infants born vaginally. 

The American College of Obstetricians and Gynecologists does not recommend a cesarean birth if you do not have genital lesions present. It is possible to have sores on your butt, thighs, or back, which would not indicate a cesarean birth.

The Importance of Educating Yourself about Cesarean Birth

Everyone should be educated about cesarean birth, especially if you have HSV and it is possible you could get a genital outbreak near the end of your pregnancy. In the United States, nearly one in three babies are born via cesarean. Even if you plan a vaginal birth, you should be knowledgeable about a cesarean section. The low-risk cesarean rate is 25.9%. Low-risk mothers are at least 37 weeks, first-time mothers, with a baby in the vertex (head down) position. Of the one in four low-risk women having a birth via cesarean, many did not plan to meet their baby that way. There are podcast episodes on cesarean birth, gentle cesarean and vaginal seeding, and when a c-section is absolutely necessary. Learning about cesarean birth can make a massive difference in understanding your options and feeling more prepared for that scenario.

Additional Risk Factors During Birth 

Some instances can increase the risk of passing HSV to your baby during birth. If you have a rupture of your membranes (your water breaks), that could increase the risk of exposure. If you have an active outbreak of genital herpes and your water breaks near your due date, a cesarean would likely be recommended.

There are some instances during labor when internal fetal monitoring is used. This method uses a tiny screw to attach an electrode on your baby’s scalp to record their heart rate. Internal monitoring is contraindicated with an active herpes infection due to an increased risk of passing the virus to your baby.


After your baby is born, even if you have HSV, you can still safely breastfeed your baby. According to the ACOG, the only time breastfeeding is contraindicated if there is a lesion on your breast. The most common place for a sore to show up would be your mouth or your genitals. I couldn’t find statistics on how often they appear on a breast. In the rare event this happens, you still need to pump milk from the affected breast to maintain your supply and continue to feed your baby from the other breast until the lesion heals. If you have blisters showing up anywhere, you want to have good hand hygiene and wash your hands to reduce the risk of touching your skin with an outbreak and then touching your baby.

If you do experience an outbreak, it should be safe to take antivirals while you are breastfeeding. The LactMed database is an excellent resource for the safety of medications during breastfeeding. Like the drugs preferred during pregnancy, acyclovir and valacyclovir are typically preferred because there is no data on famciclovir and breastfeeding. Even with the highest maternal dosages, acyclovir dosage in milk is only about 1% of a typical infant dosage and would not be expected to cause any adverse effects in breastfed infants. Since valacyclovir is a prodrug rapidly converted to acyclovir in the body, it is not expected to cause any adverse effects in breastfed infants. 

Skin-to-Skin Contact 

There is a long list of evidence-based benefits to skin-to-skin contact with your baby. I found no evidence that advised against being skin-to-skin with your baby after birth. The only caveat is that they are not exposed to lesions or blisters if you have an outbreak. If you have any blisters or a cold sore, you want to be cautious about not letting the blister come into contact with your baby and washing your hands before touching your baby.

According to the American Academy of Pediatrics, most people are exposed to HSV-1 between the ages of 1 and 5. There are some case studies in which infants were exposed to HSV-1 from a kiss from a relative or friend. If anyone has a cold sore, you would not want them to expose your baby to it. Babies are particularly susceptible to severe effects from HSV-1 before six months of age. While their immune systems are still maturing, it is always good practice for anyone holding your baby to wash their hands first. 

Talk to Your Doctor or Midwife 

You want to be upfront with your doctor or midwife if you or your partner have HSV. You can do many things to reduce the risk of transmitting this virus to your baby. Your care provider will work with you to minimize risks and keep you and your baby healthy. If you have any questions about possible exposure to HSV, you can always request a test. 

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