Finding out you’re pregnant when you have herpes can stir up a whole new wave of worry. Take a breath. The vast majority of people with herpes have perfectly healthy pregnancies and perfectly healthy babies. Let’s walk through what you actually need to know so you can replace the anxiety with information.
The big picture: herpes and pregnancy outcomes
Let’s start with the most important thing: the vast majority of people with herpes have healthy pregnancies and healthy babies. Neonatal herpes (herpes passed to a newborn) is serious but very rare, occurring in an estimated 1 in 3,000 to 1 in 20,000 live births in the U.S. And most of those cases involve mothers who contract a new herpes infection late in pregnancy, not women who had herpes before becoming pregnant.
If you’ve had herpes for a while (months or years before pregnancy), your body has already built antibodies that it shares with your baby during pregnancy. Those maternal antibodies offer significant protection. This is a case where having had herpes for longer actually works in your favor.
Neonatal herpes risk: existing infection vs. new infection
This is the most critical distinction your healthcare provider will make. The risk of transmitting herpes to your baby during delivery depends on when you were infected:
- Existing infection (acquired before pregnancy), no active outbreak at delivery, ~1–2% risk. Your body has built protective IgG antibodies that cross the placenta and protect the baby. Viral shedding rates are lower with established infection.
- Existing infection, active outbreak at delivery, ~2–5% risk. Virus is present on the skin, but maternal antibodies still provide significant protection. Cesarean delivery is recommended.
- New infection acquired in the first trimester. Low risk (similar to existing infection by delivery). The body has months to build antibodies before delivery.
- New infection acquired in the third trimester, ~30–50% risk. The body has not yet developed sufficient antibodies to protect the baby. Viral shedding is at its highest during a primary infection. This is the highest-risk scenario.
The takeaway: if you had herpes before pregnancy, you’re in the lowest-risk category. If your partner has herpes and you don’t, the most important thing is to avoid acquiring a new infection during pregnancy, especially in the third trimester. (More on this below.)
Delivery options: vaginal birth vs. cesarean section
Having herpes does not automatically mean you need a C-section. Here’s how the decision works:
- No active lesions or prodrome symptoms at labor: Vaginal delivery is recommended. This is the case for the vast majority of people with herpes.
- Active lesions or prodrome symptoms at labor: Cesarean delivery is recommended to avoid the baby coming into direct contact with the virus during passage through the birth canal.
To reduce the chance of having an outbreak when it’s go-time, ACOG (the American College of Obstetricians and Gynecologists) recommends starting daily suppressive antiviral therapy at 36 weeks of pregnancy. Studies show this reduces the risk of an outbreak at delivery by about 75% and significantly reduces the need for cesarean delivery due to herpes.
Medication during pregnancy: Is it safe?
Yes. Acyclovir and valacyclovir are considered safe during pregnancy. Here’s what the evidence shows:
- Acyclovir has the longest track record and is classified as FDA pregnancy category B (no evidence of harm in human pregnancies). It has been studied in thousands of pregnant women with no increase in birth defects.
- Valacyclovir (Valtrex) is a prodrug that converts to acyclovir in the body. It has extensive clinical data supporting its safety in pregnancy, with outcomes comparable to acyclovir.
- Both medications are recommended by ACOG for suppressive therapy starting at 36 weeks.
- Both can also be used earlier in pregnancy if needed to treat an outbreak.
The standard suppressive regimen during late pregnancy is typically acyclovir 400mg three times daily or valacyclovir 500mg twice daily, starting at 36 weeks and continuing until delivery. Your OB will tailor the approach to your specific situation.
Managing outbreaks during pregnancy
Some people notice changes in outbreak frequency during pregnancy. Hormonal shifts and immune system changes (your immune system naturally adjusts during pregnancy to protect the developing baby) can sometimes trigger more frequent outbreaks, especially in the first trimester.
If you experience an outbreak during pregnancy:
- Contact your OB or midwife. They can prescribe antiviral medication to shorten the outbreak.
- Outbreaks early in pregnancy are not dangerous to the baby. The virus does not cross the placenta during a recurrent outbreak in someone with an established infection.
- The concern is only at delivery. As long as the outbreak has healed by the time labor begins, vaginal delivery is still the plan.
- Track your prodrome symptoms so you can start treatment early if you feel an outbreak coming on.
If outbreaks become frequent during pregnancy, your doctor may start suppressive therapy earlier than 36 weeks. This is safe and commonly done.
Can early pregnancy trigger a herpes outbreak?
Yes, and it’s not uncommon. The hormonal changes and immune adaptations that happen in early pregnancy can trigger outbreaks in some people. Your body is going through a massive physiological shift, and the virus can take advantage of the temporary immune adjustment.
If this happens to you, don’t panic. An early-pregnancy outbreak does not harm the baby. Talk to your provider about treatment options, antiviral medication is considered safe throughout pregnancy when needed.
What if your partner has herpes and you don’t?
This is called a serodiscordant couple, and the priority during pregnancy is preventing you from acquiring a new herpes infection, especially in the third trimester, when a primary infection poses the highest risk to the baby.
Strategies to reduce risk:
- Your partner should take daily suppressive antivirals throughout the pregnancy. This reduces transmission risk by about 48%.
- Use condoms consistently, especially during the third trimester. Condoms reduce transmission risk by about 30% overall, and up to 96% per-act for male-to-female transmission.
- Avoid sex during your partner’s outbreaks or prodrome symptoms.
- Avoid receptive oral sex in the third trimester if your partner has oral herpes (HSV-1), to prevent acquiring genital HSV-1.
- Talk openly with your OB about your situation so they can monitor appropriately.
Breastfeeding and herpes
Breastfeeding is safe when you have herpes. The virus is not transmitted through breast milk. Both acyclovir and valacyclovir are considered safe during breastfeeding, less than 1% of the medication passes into breast milk, which is well below any level that would affect an infant.
The only precaution: if you have an active herpes lesion on or very near the breast or nipple, avoid breastfeeding from that side until the sore has fully healed. You can breastfeed from the other breast normally, and pump (then discard) from the affected side to maintain supply.
Handwashing is key. Always wash your hands thoroughly before handling your baby, especially if you have an active outbreak anywhere on your body. Herpes can be transmitted through direct skin-to-skin contact with an active sore, so keeping the baby away from any active lesions is the main precaution.
What about neonatal herpes? How serious is it?
Neonatal herpes is serious when it occurs, it can range from localized skin, eye, or mouth disease (the mildest form) to central nervous system involvement or disseminated disease (the most severe). However, it is also very rare, and the vast majority of cases are preventable with proper prenatal care.
The most important preventive measures are:
- Identifying women with genital herpes during pregnancy
- Prescribing suppressive antiviral therapy from 36 weeks
- Performing cesarean delivery when active lesions or prodrome symptoms are present at labor
- Preventing new HSV acquisition during pregnancy (especially in the third trimester)
If you have herpes and you’re pregnant, your healthcare team knows how to manage this. It’s a well-understood, well-managed situation.
The emotional side
Pregnancy brings up enough emotions on its own without herpes adding extra worry to the mix. If you’re feeling anxious about it, that’s completely normal. But here’s what I want you to hold onto: women with herpes have been having healthy babies for as long as herpes has existed. Modern medicine has made it even safer.
You’re not putting your baby at risk by having herpes. You’re being a great parent by educating yourself and working with your healthcare team. That’s exactly what good parents do. And you're already doing it by reading this. :)
