Herpes simplex virus infection in pregnancy: Clinical sciences

Herpes simplex virus, or HSV infection is a common sexually transmitted infection or STI. There are two types of this virus: HSV1 and 2. Even though HSV1 is associated with cold sores, and HSV2 with genital ulcers, both can cause genital ulcers so presentation alone is not enough to differentiate between the two. Determining the HSV subtype is important as it can provide information on the risk of recurrence.

Now, the infection itself carries some risks. A primary outbreak in the first trimester of pregnancy can result in neonatal chorioretinitis, microcephaly, and skin lesions, while a primary outbreak near the time of delivery significantly increases the risk for neonatal transmission.

Recurrent infections can also be transmitted to the neonate during delivery through intrapartum exposure to the virus in the maternal genital tract and can result in disseminated disease or CNS disease, with the possibility for long-term neurologic impact.

When a patient presents with a chief concern suggesting HSV infection in pregnancy, start with a focused history and physical examination.

History might reveal a prior HSV outbreak. Additionally, the patient might have a prior documented history of positive HSV antibodies. They might report single or multiple genital lesions, which are possibly painful. A primary outbreak typically involves multiple painful lesions, whereas a recurrent outbreak more commonly presents as a single ulcer that is mildly painful or non-painful. Be sure to ask about prodromal symptoms that occur with recurrent infections including burning or tingling in the area where the outbreak normally occurs.

Lastly, patients might report vulvar pruritus, dysuria, or systemic symptoms such as fever, headache, or malaise.

When it comes to the physical exam, the focus is on the genital area. You might find perineal erythema and genital ulcers. Ulcers could be single and unilateral or multiple and bilateral. Additionally, the exam might reveal tender inguinal lymphadenopathy if there is a primary infection.

Now, if the patient can tolerate it, perform a speculum exam to evaluate for cervical lesions and consider testing for concurrent sexually transmitted infections and/or vaginitis if clinically indicated.

Here’s a high-yield fact! HSV is typically transmitted through direct contact and has an incubation period of 2-12 days.

Alright, if the patient has a prior history of genital herpes, we are talking about a recurrent infection.

The current outbreak is treated with antiviral medication, such as acyclovir or valacyclovir. Additionally, all pregnant individuals with a history of HSV require suppressive therapy with antivirals beginning at 36 0/7 weeks gestation through delivery. Suppressive therapy not only reduces the risk of an outbreak at the time of delivery but also decreases asymptomatic shedding, reducing the risk of acquired intrapartum neonatal herpes.

Finally, any patient who presents in labor with a history of HSV requires assessment for both prodromal symptoms and any active genital lesions, as these are contraindications to a vaginal delivery. A thorough perineal, sterile speculum and visual cervical examination must be performed to assess for genital ulcers or lesions. If there are no prodromal symptoms or lesions, the patient can continue laboring and undergo a vaginal delivery. However, if prodromal symptoms or an active lesion are present, a C-section is recommended to decrease the risk of neonatal herpes.

After delivery, notify the pediatrics team of the patient’s HSV status, so that they can properly examine the neonate for symptoms of neonatal transmission. Okay, let’s go back and talk about patients with no prior history of genital herpes.

Your next step here is to order a direct viral test on the lesion, which involves unroofing a lesion with a swab and sending collected fluid for viral culture and/or PCR-based HSV antigen detection. Additionally, obtain a type-specific serologic test to check for HSV1 and/or HSV2 antibodies. Keep in mind that If a patient reports a recent history of genital ulcers or lesions but does not currently have one, or has a clinical history that otherwise might suggest HSV, serology alone is enough.