What causes herpes to flare up?

Approximately 22% of pregnant women have genital herpes. While it's a manageable condition in most adults, herpes can be serious and even fatal for newborns. Fortunately, your risk of spreading it to your baby is very low, especially if you contracted it before your pregnancy. If you have it, your doctor will take measures to prevent you from passing it to your baby during delivery.
Usually your first herpes outbreak is the worst. Outbreaks generally become milder because your body makes antibodies to the virus. There's no evidence that pregnancy causes herpes outbreaks, but approximately 75% of pregnant women with herpes will have an outbreak at some point during their pregnancy.
Herpes can lie dormant for many years. Sometimes what appears to be a new case of herpes is actually a dormant case that is causing symptoms for the first time. If you don't know whether you have herpes, talk to your doctor about being tested.
After your initial herpes infection subsides, the virus travels to a bundle of nerves at the base of your spine. During this period it's latent, and you won't have any symptoms. Recurrent outbreaks happen when the virus travels from your nerves to the surface of your skin. Recurrent outbreaks may be triggered by:
The difference between genital herpes and oral herpes
Genital herpes can be caused by two different viruses, herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). Oral herpes is usually caused by HSV-1. About 50% to 80% of adults have HSV-1. By age 50, about 90% of adults have been exposed to it. Oral herpes can be spread from the mouth to the genitals through oral sex, which is why some cases of genital herpes are caused by HSV-1.
Herpes in newborns
Both types of herpes viruses can cause neonatal herpes in newborns. It is most commonly spread to babies from their mothers during childbirth. However, babies can also get neonatal herpes from being kissed by someone with a cold sore. Rarely, herpes can be spread by touch, if someone touches a cold sore or genital sore and then touches a baby.
Neonatal herpes is a serious infection. It can cause:
- Blindness
- Inflammation of the membrane around your baby's brain
- Seizures
- Deafness
- Sores on the skin, eyes, genitals, or mouth
- Damage to your baby's organs, including the liver, lungs, and heart
Fortunately, neonatal herpes is also very rare, occurring in fewer than 0.1% of newborns born in the US each year. Most women with herpes give birth to healthy babies. The risk is greatest if you contract herpes late in pregnancy, since you won't have built-up antibodies to pass along to your baby. A new infection is also more likely to be active and present in the birth canal during delivery.

SLIDESHOW
16 Early Signs & Symptoms of Pregnancy: Could You Be Pregnant? See SlideshowHow can you control your herpes while pregnant?
There are some steps you and your healthcare provider can take to minimize the risk to your baby even more. These include:
- Make sure your midwife or obstetrician knows you have herpes.
- If you have an active outbreak at the time of delivery, you may need to have a C-section.
- Let your doctor know if you have any symptoms of an outbreak, such as tingling, itching, or pain, even if you don't have any sores.
- If you have a vaginal delivery, your doctor may not break your water since it may help protect the baby in the birth canal.
- A vacuum or forceps won't be used unless medically necessary since they can cause a break in your baby's skin that may allow the virus to get in.
- A fetal scalp monitor won't be used unless medically necessary because it can break the baby's skin and allow the virus to enter.
- Your doctor may prescribe antiviral medicine such as acyclovir to reduce your risk of having an outbreak during delivery or spreading herpes to your baby.
- Since herpes can also be spread from cold sores, don't allow anyone with a cold sore to kiss your baby.
Once your baby is home, monitor them for about 3 weeks. If you notice any of the following symptoms, take your baby to the pediatrician and let them know you have herpes:
- Skin rash
- Fever
- Crankiness
- Lack of appetite
Preventing herpes during pregnancy
If you don't have herpes, it's important not to get it during pregnancy. If you test negative but your partner has genital or oral herpes, take the following precautions to avoid getting it:
- Abstain from sex during outbreaks and use condoms at all other times.
- Consider abstaining from sex completely during the last trimester.
- Don't let your partner perform oral sex on you if they have oral herpes.
- If you aren't sure if your partner has herpes, you may want to ask them to be tested.
Centers for Disease Control and Prevention: "Genital Herpes - CDC Fact Sheet." NHS: "Neonatal herpes (herpes in a baby)."
UT Southwestern Medical Center: "Genital herpes and pregnancy: Understanding the risks."
UpToDate: "Patient education: Genital herpes (Beyond the Basics)."
Top Can Pregnancy Cause Herpes to Flare Up Related Articles
Childbirth Delivery Methods and Types
Learn about the pros and cons of various childbirth methods, such as the Bradley method, C-section, natural childbirth, water birth, Lamaze, and vaginal delivery. Read about birthing centers, hospital and home births, midwives, and doulas.16 Early Signs & Symptoms of Pregnancy: Could You Be Pregnant?
What are the early signs and symptoms of pregnancy? Can you know before your missed period? Read about nausea and vomiting (morning sickness), bloating, tender breasts, and more. Explore first trimester symptoms of pregnancy and learn what week pregnancy symptoms start.Am I Pregnant Quiz
What are early pregnancy symptoms? In some women, symptoms range from a missed period to feeling lightheaded. Others may experience typical "morning sickness" and food cravings. Could you be pregnant? Take the quiz!Genital Herpes
What's going on down there? WebMD shows you pictures of genital herpes symptoms and treatments -- and how to avoid getting the virus in the first place.What Is Genital Herpes in Women?
Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex virus (HSV). Symptoms of genital herpes include painful blisters and often fever, body aches, and swollen lymph nodes for the first outbreak. Genital herpes is diagnosed with lab tests to test for the presence of the virus. Treatment for genital herpes includes antiviral medications to shorten the duration of the outbreak or reduce the risk of future outbreaks. There is no cure for genital herpes. Condoms may help prevent the spread of genital herpes.Genital Herpes Quiz
What is genital herpes? Learn the causes, symptoms in men and women, and treatments for this common sexually transmitted skin disease.How Is A Cesarean Delivery Done?
Cesarean delivery is the surgical delivery of a baby by making an incision in the mother’s abdominal wall and uterus. Although cesarean delivery is generally safe, it should be performed during certain circumstances. About 30% of all babies in the United States are born through cesarean delivery.Labor and Delivery
Early and later symptoms and signs of labor and delivery are unique to each woman. Early signs of labor are "lightning" and passing the mucus plug. Later symptoms and signs that labor that labor is are the woman's water breaking, and when contractions begin. There are three stages of labor, stage 1 is the longest and occurs when the cervix begins to thin and dilate. During stage 2 of labor the baby passes through the birth canal and remains there until delivery, and stage 3, is when the baby is delivered.Pregnancy Myths and Facts Quiz
Being pregnant is a delicate time for both mother and baby. Take this pregnancy myths and facts quiz to separate the myths and facts about being pregnant, and learn the truth behind healthy pregnancies!Pregnancy Planning (Tips)
Pregnancy planning is an important step in preparation for starting or expanding a family. Planning for a pregnancy includes taking prenatal vitamins, eating healthy for you and your baby, disease prevention (for both parents and baby) to prevent birth defects and infections, avoiding certain medications that may be harmful to your baby, how much weight gain is healthy exercise safety and pregnancy, travel during pregnancy.Sexually Transmitted Diseases and Pregnancy (STDs)
When you are pregnant, many sexually transmitted diseases (STDs) can be especially harmful to you and your baby. These STDs include herpes, HIV/AIDS, genital warts (HPV), hepatitis B, chlamydia, syphilis, gonorrhea, and trichomoniasis. Symptoms include bumps, sores, warts, swelling, itching, or redness in the genital region. Treatment of STDs while pregnant depends on how far along you are in the pregnancy and the progression of the infection.What Happens When You Get Shingles When Pregnant?
Becoming infected with chickenpox during pregnancy could cause birth defects in your unborn child. Likewise, shingles could also cause problems for your unborn child. If you are pregnant and haven't had chickenpox, avoid exposure to infected people. Zostavax, the shingles vaccine, can reduce the incidence of shingles by half. Women should wait at least three months after receiving the vaccine before trying to get pregnant.Stages of Pregnancy: Week by Week
See pictures on the various stages of pregnancy. See and learn what changes a woman's body goes through and view fetal images of how her baby grows during the 1st, 2nd and 3rd trimesters.What Do Herpes Sores Look Like at Different Stages?
Herpes simplex virus 1 (HSV-1) and simplex virus 2 (HSV-2) are the two types of herpes virus and will look different as they develop during five stages.What Is Better: Normal or Cesarean Delivery?
Delivery of a full-term newborn baby (37-42 weeks from the last menses of mother) through the vagina without the use of forceps or vacuum for assistance is called a normal delivery of a baby. It is the most preferred option of delivery in the United States, that is, almost two of every three deliveries are normal.What Triggers Herpes?
Once a person is infected with herpes, the virus may stay dormant or quiet within the nerves. It is not known what exactly may trigger the symptoms.