Herpes simplex virus (HSV) is a common viral infection causing sores around the mouth (cold sores) or genital area (genital herpes). During pregnancy, understanding HSV’s implications is important for the health of both the pregnant individual and the developing baby. This article covers herpes during pregnancy, including testing, risks, and management.
Understanding Herpes and Pregnancy Testing
Routine, universal testing for herpes simplex virus is not standard practice during pregnancy. Healthcare providers perform testing under specific circumstances. These include when a pregnant individual exhibits symptoms like sores or blisters, has a partner with a known herpes infection, or has a history of herpes with an unknown current status.
Herpes simplex virus exists in two main types: HSV-1, commonly associated with oral herpes, and HSV-2, primarily linked to genital herpes. Both types can cause genital infections.
When symptoms are present, a healthcare professional may perform a swab test of an active lesion to collect fluid or cells for viral culture or PCR (polymerase chain reaction) testing. If no active lesions are present, a blood test for antibodies (type-specific serologic test) can indicate past exposure to the virus. Blood tests do not indicate an active infection and can sometimes yield false-positive results.
Risks of Herpes During Pregnancy
Herpes infection during pregnancy carries varying risks depending on whether it is a primary (first-time) infection or a recurrent one. A primary genital herpes infection acquired late in pregnancy, especially in the third trimester, poses the highest risk of transmission to the baby. This heightened risk, ranging from 30% to 50%, occurs because the pregnant individual has not yet developed protective antibodies to pass to the fetus.
In contrast, the risk of transmission from a recurrent infection is significantly lower, less than 1% to 3%. This is because maternal antibodies developed from previous infections offer some protection to the baby.
Neonatal herpes is a serious concern during pregnancy. While rare, occurring in about 10 out of every 100,000 births, it can have severe consequences for newborns, leading to neurological disability, severe health problems, or even death.
Other potential complications, though less common, include preterm labor and low birth weight, particularly with primary infections. Miscarriage and intrauterine growth restriction have also been associated with primary infections in early pregnancy.
Management and Prevention Strategies
Managing herpes during pregnancy involves antiviral medications. Acyclovir or valacyclovir are prescribed to suppress outbreaks and are considered safe for use during pregnancy. These medications reduce the frequency and severity of herpes recurrences.
Healthcare providers recommend starting suppressive antiviral therapy around 36 weeks of gestation. This approach aims to minimize the chance of an active outbreak occurring at the time of delivery, which can help reduce the need for a cesarean section.
For individuals who do not have herpes, several prevention strategies can reduce the risk of acquiring the virus during pregnancy. Avoiding direct skin-to-skin contact with active herpes lesions is important. Consistent use of condoms during sexual activity can reduce, but not eliminate, the risk of transmission. It is advisable to abstain from sexual contact with partners experiencing an active outbreak. To prevent genital HSV-1 infection, pregnant individuals should avoid oral sex if their partner has oral herpes (cold sores).
Protecting the Newborn
Protecting the newborn from herpes infection primarily focuses on preventing contact with the virus during delivery. The main concern is the baby coming into contact with active herpes lesions or viral shedding in the birth canal.
If active genital herpes lesions or prodromal symptoms (like tingling or burning) are present at the onset of labor, a cesarean section (C-section) is recommended. This surgical delivery method significantly reduces, though does not entirely eliminate, the risk of the baby acquiring the virus. A C-section is especially important if a pregnant individual acquires a primary herpes infection late in pregnancy, as the risk of transmission is highest in this scenario.
During labor, invasive procedures such as the use of fetal scalp electrodes, forceps, or vacuum extractors should be avoided if active lesions are present. These instruments can cause minor breaks in the baby’s skin, potentially allowing the virus to enter.
After birth, it remains important to protect the newborn from herpes. Anyone with a cold sore (oral herpes) should avoid kissing the baby, and thorough hand hygiene is recommended for all caregivers.