While most women with genital herpes have healthy babies, a small number pass the virus on to their babies during labor and delivery. For this reason, it is especially important for pregnant women to recognize the symptoms of this disease, and to seek immediate medical treatment if they think they could be infected. Pregnant women also should tell their health care provider if they have had herpes in the past, so the provider can take any necessary steps to protect their babies from the infection.
What causes herpes?
Herpes is caused by herpes simplex viruses, which are similar to the viruses that cause chickenpox and shingles. After the initial infection, herpes simplex viruses can hide within nerve cells, where the body's immune system cannot reach them. Then, under the right conditions, the viruses can launch new attacks.
There are two main kinds of herpes simplex viruses:
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Type 1, which is usually associated with cold sores around the mouth and lips
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Type 2, which is usually associated with genital sores
However, either type can infect oral or genital areas, and pregnant women with genital sores caused by either form of herpes simplex virus can pass the infection on to their babies.
Environmental influences (such as heat, friction, sexual intercourse, menstruation, fever or emotional stress) may trigger a new outbreak of sores. The average infected person experiences four or five recurrences a year. The outbreaks tend to become less frequent and less severe with time.
How is herpes transmitted?
Herpes infections are transmitted by direct contact with an infected person. A person can become infected with genital herpes during sexual intercourse or oral-to-genital contact with an infected person. An infected person can spread the virus from one part of the body to another with unwashed hands. For example, persons who have cold sores always should wash their hands thoroughly after any contact with saliva before touching the genital area.
Children often become infected with type 1 herpes during the first years of life. This may occur when a child has direct contact with herpes sores (for example, being kissed by a person with a cold sore) or with virus-containing saliva (for example, touching their lips with their fingers after contact with infected saliva).
What are the symptoms of genital herpes?
Shortly after a person contracts herpes, clusters of small blisters may appear in the genital area. These blisters itch and become painful. Then they break, leaving painful ulcers. Fever, fatigue, aches and pains, and a urethral or vaginal discharge often occur. Health care providers diagnose herpes by examining the sores or by doing a swab of the blisters, and then ordering a viral culture.
The first, or primary, attack usually ends within 7 to ten days but may last as long as two to four weeks if the blisters become infected with bacteria. Recurrent outbreaks generally are shorter and milder.
However, most herpes infections, both primary and recurrent, do not produce any symptoms. These symptomless (sometimes called silent) infections generally go undiagnosed. As a result, as many as 90 percent of people who are infected with genital herpes do not know they have it (4). However, individuals with symptomless infections can pass the virus on to others, including a newborn baby.
How is herpes infection treated in adults?
Three antiviral drugs can shorten the duration of an attack and help alleviate symptoms:
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Acyclovir
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Valacyclovir
- Famciclovir
These drugs are recommended when an individual has a primary attack of herpes with severe symptoms. When taken preventively, these drugs reduce the number of attacks in individuals who have them often.
Acyclovir, which generally is given to pregnant women, can be given intravenously, orally or in ointment forms. The oral form is more effective than the ointment for outpatient treatment.
What risks does herpes pose during pregnancy?
About 1 in 4 pregnant women has been infected with genital herpes, although most do not know it (1). Fortunately, only a small minority will pass the infection on to their babies.
Women who acquire genital herpes for the first time near the time of delivery have a 30 to 50 percent chance of passing the infection on to their babies during a vaginal delivery, whether or not they have symptoms (3, 5). The risk is so high because a newly infected pregnant woman has not yet produced the disease-fighting antibodies that could help protect her baby during delivery. Studies suggest that about 2 percent of pregnant women who have not had herpes previously acquire it during pregnancy (6, 7).
Women who have had herpes before pregnancy and have a flare-up or silent infection at the time of vaginal delivery have only about a 3 percent chance of infecting their babies (3, 5). Sometimes, what appears to be a first, severe episode of herpes during pregnancy actually can be a flare-up of an old silent infection. These women have a low risk of infecting their babies. Blood tests sometimes can help determine whether a woman has a new infection or a recurrence of an old one.
Are there other ways in which a baby can become infected?
While most babies get herpes from their mothers at delivery, on rare occasions, a baby can become infected before birth (3). A small number of babies acquire herpes after birth (for example, if someone with a cold sore [oral herpes] kisses the baby). A person with a cold sore should not kiss a baby or touch a baby after touching the cold sore.
What are the symptoms of herpes infection in the newborn?
Some infected newborns develop skin or mouth sores or eye infections. When the infection remains limited to these organs, most infected babies go on to develop normally, although serious permanent damage to nerves or the eyes can occur.
However, herpes infections in newborns often spread to the brain and many internal organs. Infected babies may appear irritable, eat poorly and have seizures. Even with treatment, about half of the infants with widespread infections involving the internal organs die, as do about 10 percent of those with brain infections (3). Many babies who survive widespread infections and brain infections develop lasting disabilities, such as mental retardation, cerebral palsy, seizures, and vision or hearing loss (3).
How are infected newborns treated?
Infected newborns are treated with acyclovir (3). This drug is quite successful in treating localized infections of the eyes, skin or mouth. It is important to treat infected babies early, before the infection spreads, because acyclovir is less effective once the infection has spread to the brain and other internal organs.
How can the baby be protected from infection if the mother has herpes?
If a pregnant woman has a history of genital herpes, her health care provider will examine her carefully for any signs of infection when she goes into labor. When a woman has an active infection (primary or recurrent) at the time of delivery, her baby usually can be protected from infection by a cesarean delivery. A vaginal delivery is safe for most women with recurrent herpes as long as they don't have signs of infection at delivery.
Some doctors recommend that women who have had a primary infection during pregnancy or who have recurrent flare-ups take acyclovir for the last month of pregnancy. Some studies suggest that this treatment may help prevent active infections during labor and delivery and, possibly, help reduce the need for cesarean delivery (8, 9). Acyclovir is considered safe in pregnancy and has not been associated with birth defects in more than 20 years of use (9).
Several studies, however, show that between 60 and 70 percent of mothers of infants with newborn herpes infections have no signs or symptoms of herpes at delivery (8). Doctors have not yet developed a good way to protect babies when their mothers have silent infections at delivery. Virus-culture tests are not helpful during labor and delivery because it takes one to three days to get test results. Researchers are seeking to develop vaccines, as well as blood tests that may offer rapid diagnosis during labor, in order to prevent more newborn infections.
How can a woman avoid getting herpes during pregnancy?
A pregnant woman who does not have a history of herpes should take special precautions to stay infection-free, especially in the last trimester, when risk to the baby is highest. If her partner has a history of herpes, she may want to ask her health care provider about taking a blood test to find out whether or not she is infected (she could have had a silent infection). If she does not have herpes, her doctor may recommend that she avoid intercourse and oral-genital contact in the last trimester.
Before the last trimester, her partner should avoid intercourse when he has symptoms of infection and wear a condom when he does not have symptoms (because he cannot tell if he has a silent infection).
Does the March of Dimes fund research on newborn herpes infections?
The March of Dimes supports research aimed at preventing and treating newborn herpes infections. For example:
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One grantee is seeking to develop a vaccine for newborns that can boost their immune response and help prevent brain damage and deaths resulting from newborn herpes infection.
- Another is investigating how the virus invades the central nervous system of the newborn in order to develop antiviral drugs that can prevent complications of newborn herpes infections.
References
- Centers for Disease Control and Prevention. STD Prevention: Genital Herpes. Updated May 24, 2004, accessed 6/28/04.
- Centers for Disease Control and Prevention. Tracking the Hidden Epidemics 2000: Herpes. Last reviewed 4/15/04, accessed 6/28/04.
- Arvin, A. and Whitley, R. Herpes Simplex Virus Infections. In Remington, J. and Klein, J. (eds.): Infectious Diseases of the Fetus and Newborn Infant, Fifth Edition, Philadelphia, W.B. Saunders Company, 2001, pages 425-446.
- American Social Health Association. Herpes: Get the Facts. Accessed 6/28/04.
- American College of Obstetricians and Gynecologists. Management of Herpes in Pregnancy. ACOG Practice Bulletin, number 8, October 1999.
- Brown, Z.A. Effect of Serologic Status and Cesarean Delivery on Transmission Rates of Herpes Simplex Virus from Mother to Infant. Journal of the American Medical Association, volume 289, number 2, January 8, 2003, pages 203-209.
- Brown, Z.A., et al. The Acquisition of Herpes Simplex Virus During Pregnancy. The New England Journal of Medicine, volume 337, number 8, August 21, 1997, pages 509-515.
- Watts, D.H., et al. A Double-Blind, Randomized, Placebo-Controlled Trial of Acyclovir in Late Pregnancy for the Reduction of Herpes Simplex Virus Shedding and Cesarean Delivery. American Journal of Obstetrics and Gynecology, volume 188, number 3, March 2003, pages 836-843.
- Sheffield, J.S. Acyclovir Prophylaxis to Prevent Herpes Simplex Virus Recurrence at Delivery: A Systematic Review. Obstetrics and Gynecology, volume 102, number 6, December 2003, pages 1396-1403.
March 2005
