Herpes simplex virus (HSV) is a common viral infection, typically categorized into two types: HSV-1 (oral herpes/cold sores) and HSV-2 (genital herpes). Both types can infect various body areas. Transmission occurs through direct contact with lesions or bodily fluids, even when no symptoms are present.
Herpes and Miscarriage Risk
While historically thought to increase miscarriage risk, a first episode of genital herpes in the first trimester does not typically elevate this risk or lead to developmental problems.
The concern with primary infections, especially those acquired later in pregnancy, stems from the mother’s immune system not having sufficient time to develop protective antibodies. These antibodies are then transferred to the fetus, providing a natural defense. Without them, the risk of the virus being transmitted to the baby during delivery is higher.
For individuals who had herpes prior to pregnancy, recurrent outbreaks generally do not pose a direct threat of miscarriage. Their established immune response means protective antibodies are already present and can cross the placenta, shielding the developing fetus. A definitive causal link between recurrent herpes infections and miscarriage is not firmly established, with a very low risk of intrauterine fetal infection.
Other Pregnancy Complications from Herpes
Beyond miscarriage, herpes in pregnancy can lead to other serious complications, particularly for the newborn.
Untreated genital herpes, especially if acquired in the first or second trimester, has been associated with more than double the risk of preterm delivery. However, antiviral treatment during pregnancy can reduce this risk, making it comparable to that of uninfected individuals.
The most significant concern is neonatal herpes, a severe and potentially fatal condition affecting newborns. This occurs when the baby is exposed to the virus, most commonly during passage through the birth canal. Neonatal herpes can lead to widespread infection, causing lasting damage to the central nervous system, organ damage (like brain swelling), intellectual disability, or even death.
The risk of neonatal herpes is highest (30-50%) with a primary infection late in pregnancy, due to the absence of protective maternal antibodies. For mothers with recurrent herpes, the transmission risk is very low (typically less than 1%) because these antibodies are present. While rare, congenital herpes (infection in utero) is possible, though most infections occur during birth.
Management of Herpes During Pregnancy
Managing herpes during pregnancy involves careful monitoring and treatment to protect both the pregnant individual and the baby.
Diagnosis typically involves taking a sample from an active sore for laboratory testing to identify the virus type, or a blood test can detect antibodies, indicating past exposure. Open communication with a healthcare provider about any history or symptoms of herpes is important.
Antiviral medications, such as acyclovir and valacyclovir, are commonly used for treatment. These medications may be prescribed for primary herpes infections during pregnancy. Suppressive therapy is often recommended from around 36 weeks of gestation until delivery for individuals with a history of recurrent genital herpes. This therapy helps reduce the likelihood of outbreaks and asymptomatic viral shedding near the time of birth, which can decrease the need for a Cesarean section.
The decision regarding the method of delivery is based on the presence of active lesions or prodromal symptoms at the onset of labor. If active lesions are present, a Cesarean section is recommended to minimize the baby’s exposure to the virus during birth. If no active lesions or symptoms are present, a vaginal delivery is generally considered safe.
Preventing Herpes Transmission in Pregnancy
Preventing herpes transmission is crucial for safeguarding both the pregnant individual and the baby.
For those without herpes, avoiding acquisition during pregnancy, particularly in the third trimester, is important. If a partner has herpes, abstaining from sexual contact during active outbreaks is advisable.
Consistent condom use for all sexual activity helps reduce transmission risk, as the virus can shed even without visible symptoms. Partners with herpes may also consider daily antiviral medication to further reduce transmission. Avoiding oral sex if a partner has active cold sores can prevent genital herpes acquisition.
Maintaining good hand hygiene after touching any sores is important. After birth, individuals with cold sores should avoid kissing the newborn and ensure thorough hand washing before contact to prevent postnatal transmission.