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There are over 100 herpesviruses, and of those 8 affect humans. The two that are most common are the herpes simplex virus type 1 and type 2. HSV-1 and HSV-2 are common skin conditions. If you have HSV-1 or HSV-2, you should not be ashamed or embarrassed. The truth is that this virus affects a considerable portion of the population, and one in five women. Neonatal herpes is a serious condition that can have detrimental effects. The good news is that transmission rates during pregnancy and birth are low. Learn about 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 that are most common are the herpes simplex virus type 1 and type 2. HSV-1 and HSV-2 are common skin conditions. If you have HSV-1 or HSV-2, you should not be ashamed or embarrassed. 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

Herpes Simplex Virus Type 1 (HSV-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 and cause genital herpes. Herpes Simplex Virus Type 2 (HSV-2) is frequently referred to as genital herpes and is sexually transmitted. The infections caused by both HSV-1 and HSV-2 are lifelong, and there is no cure. 

Signs and Symptoms

Both types of herpes infections are mostly asymptomatic and can even 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 in 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 appearing 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 the occur before a blister are called prodromal symptoms.


According to the World Health Organization, an estimated 3.7 billion people under age 50 have HSV-1. That is a total of 67% of the world population. The prevalence differs a lot among different countries and is 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 were living 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. 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 perform 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.


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 the 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 women acquire 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 be a contributing factor as to why an outbreak is more likely.

Neonatal Herpes

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, and babies who have HSV receive intravenous acyclovir.

In utero infection is very 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 who has HSV should be on preventing transmission.

Risks of Transmitting HSV to Your Baby

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

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

There are some signs to keep an eye out for in your baby, and these include 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 especially important in the third trimester. Even if your partner has no visible symptoms, use condoms throughout your pregnancy. Keep in mind, condoms are not 100% effective, but they can reduce the risk of transmission. If there are any symptoms present, you should 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 currently available. Currently, there are clinical trials on vaccines that are expected to be completed in 2023. 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 the use of 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 thought to be 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 are those that show up before an outbreak and include fever, swollen lymph nodes, headache or body aches, pain when you urinate, 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 one study that focused on women who had HSV present 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.

If you are concerned about the risks of transferring HSV to your baby and want to explore the option of a cesarean birth please discuss all of the pros and cons with your doctor.

Additional Risk Factors During Birth

Some instances can increase the risk that you pass 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, and this is usually contraindicated with an active herpes infection due to an increased risk of passing the virus to your baby. Internal monitoring uses a tiny screw to attach an electrode on your baby’s scalp to records their heart rate.


After your baby is born, even if you have HSV, you can still safely breastfeed your baby. According to the CDC 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 would show up 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, 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. Similar to the drugs preferred during pregnancy, typically acyclovir and valacyclovir are preferred because there is no data on famciclovir and breastfeeding. Even with the highest maternal dosages, the dosage of acyclovir 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 that is 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 to this is that they are not exposed to lesions or blisters if you have an outbreak. If you have any blisters or a cold sore, 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 who will be holding your baby to wash their hands first.

Talk to Your Doctor or Midwife

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