Genital Herpes in Pregnancy
Joint BASHH and RCOG National UK Guideline for the Management of Herpes Simplex Virus (HSV) in Pregnancy and the Neonate (2024 Update).
NICE CKS Herpes Simplex – Genital. Last revised May 2024.
Background Information
Neonatal Herpes
There are 3 main forms of disease presentation:
- Skin, eye and mouth disease (SEM)
- Vesicular lesions or ulcers on skin / eye / mouth
- No CNS or visceral organ involvement
- Very good prognosis, apart from risk of recurrent SEM disease during childhood
- CNS disease (meningoencephalitis)
- Lethargy, poor feeding, seizures
- +/- SEM disease
- Poor prognosis
- Disseminated disease
- Commonly present as sepsis-like picture
- Very poor prognosis
Diagnosis
Investigation and Diagnosis
Refer suspected cases to GUM
- 1st line: swab for viral PCR
- Other investigations
- HSV serology (esp. in 3rd trimester and if type is not known)
- Full STI screening
Do not delay treatment whilst awaiting test results.
Management
The following conservative care advice should be offered to ALL patients.
General advice:
- Increase fluid intake
- Urinate in a bath or with water flowing over the area
- Abstinence from sexual contact during lesion recurrences / prodromes
Self-care measures
- Saline bathing
- Analgesia (paracetamol / ibuprofen)
- Note that NSAIDs should be avoided from 20 weeks of gestation onwards due to the risk of premature ductus arteriosus closure and oligohydramnios
- Topical petroleum jelly / anaesthetic agent (e.g. 5% lidocaine ointment)
Primary Herpes Infection (First Episode)
Antiviral Therapy
Antiviral therapy is indicated in ALL pregnant patients with primary herpes infection. There are 2 phases of antiviral therapy:
- Acute / episodic antiviral treatment
- Followed by suppressive antiviral therapy later on
Do NOT delay acute/episodic treatment while awaiting microbiology results (i.e., PCR)
Acute / Episodic Antiviral Treatment
This should be initiated once primary genital herpes is suspected clinically
Offer a 5-day course of antiviral therapy
- Oral aciclovir 400mg TDS for 5 days OR
- Oral valaciclovir 500mg BD for 5 days
IV antivirals are reserved for disseminated HSV infections.
Note that the following antivirals should NOT be used in pregnancy:
- Ganciclovir is contraindicated (also note that it is used to treat CMV, not HSV)
- Famciclovir has limited safety data, thus avoided
Suppressive Antiviral Treatment
Choice of antiviral: oral aciclovir or valaciclovir with a lower daily dose (compared to acute treatment)
The initiation timing and treatment duration depend on when the primary herpes infection occurred:
- 1st / 2nd trimester infection → start from 32 weeks of gestation and continue until delivery
- If there is a high risk of premature delivery → start from 22 weeks of gestation instead
- 3rd trimester infection → start immediately and continue until delivery
The purpose of suppressive antiviral treatment is to reduce viral shedding, reduce risk of neonatal transmission (highest if primary infection is acquired within 6 weeks of delivery), and risk of recurrence.
Note that the following antivirals should NOT be used in pregnancy:
- Ganciclovir is contraindicated (also note that it is used to treat CMV, not HSV)
- Famciclovir has limited safety data, thus avoided
Mode of Delivery
Caesarean section is the recommended mode of delivery if any of the following:
- 3rd trimester infection (from 28 weeks onwards; esp. if ≤ 6 weeks to delivery)
- Delivery expected within the next 6 weeks
If Caesarean section is not indicated: expectant vaginal delivery is the primary option
History of Genital Herpes
For patients with a history of genital herpes prior to pregnancy:
Offer suppressive antiviral therapy to all patients (regardless of whether recurrence occurs during pregnancy)
- Same regimen as if primary infection (see the section on suppressive antiviral therapy under the primary infection section)
However, this alone is NOT an indication for a Caesarean section
Recurrent (Not Primary) Herpes Infection
This refers to the scenario where a woman develops a symptomatic recurrent (not primary) episode during pregnancy
Antiviral therapy (acute/episodic treatment) is not routinely indicated
- Recurrent infection is usually mild, resolving in 7-10 days without antivirals
- If indicated (e.g., distressing episode) follow regimen as if primary infection
It is important to note that a “first clinical episode” of genital herpes does not always represent a true primary infection (i.e., the first-ever HSV exposure with no pre-existing antibodies). While certain clinical features can provide clues — such as primary infections typically presenting more severely with multiple, bilateral, and painful lesions often accompanied by systemic symptoms (e.g., fever, malaise), compared to milder, unilateral lesions without systemic upset seen in recurrences — definitive differentiation requires laboratory confirmation. This should be performed using lesion PCR for HSV typing, alongside type-specific HSV serology (IgG for HSV-1 and HSV-2) to establish whether prior infection and immunity are present.
Breastfeeding and Genital Herpes
- Antivirals (aciclovir and valaciclovir) used to treat herpes are not harmful to infants
- It is safe to breastfeed if there is no herpetic lesion on the breast
- Avoid milk contamination (e.g. touching the breast during hand expression / via the pump)
References