Genital Herpes in Pregnancy

This document is mainly based on the RCGP¹ and GUM guidance.² It should be read alongside the main article on Genital Herpes Simplex.

Aetiology, epidemiology, transmission, presentation, complications and differential diagnosis of herpes simplex virus (HSV) infection are dealt with in the main article and will not be discussed here. This article concentrates on the management issues specific to genital herpes infection during pregnancy.

If you see a pregnant woman with genital herpes, the most important questions to ask are:

1. Is this a first episode or a recurrence?
2. What trimester of pregnancy is the woman in?

Management of first episode infection

1st and 2nd trimester

• Confirm diagnosis. Viral isolation and typing should be carried out using ulcer swabbing, viral culture and/or PCR. Testing of paired sera, if a booking specimen is available, may help identify primary from recurrent infection.
• Manage symptomatically according to patient need. Follow the same procedure as that with primary infection in a non-pregnant person as outlined in the main article. Refer the woman to a genito-urinary medicine clinic.
• Although aciclovir is not licensed in pregnancy, there is substantial clinical evidence gathered over many years to support its use.^1,2,3,4 It can be given orally for 5 days if appropriate (i.e. within 5 days of onset of symptoms, or if new lesions are still forming).
• Inform other people involved in the woman's antenatal care (midwife, obstetrician).
• Aim for a vaginal delivery.
• The same points regarding counselling and contact tracing as are listed in the main Genital Herpes Simplex article should also be covered as part of your management.

• When primary infection occurs during the 3rd trimester it carries the greatest risk of neonatal infection. The quoted risk of neonatal herpes, calculated from five studies, when the baby is delivered vaginally was 41% in a 2002 RCOG document.⁵
• The mother will need referral to an obstetrician.
• A Caesarean section should be considered, especially if >34/40 gestation. (The woman can still be shedding the virus at delivery, even if there are no visible lesions.)¹
• Caesarean section for the prevention of neonatal herpes has not been evaluated in randomised controlled trials and may not confer complete protection.²
• Consider aciclovir for mother now and for baby after delivery, especially if vaginal delivery is unavoidable.
• Again counselling and contact tracing are needed.

Management of recurrent infection

Recurrent genital herpes is associated with a much smaller risk of neonatal herpes.⁵ One study reported a transmission rate of 3%⁶ while another study reported a rate of 0%.⁷
• Confirm the diagnosis.
• Maternal antibodies will give some protection to the baby but neonatal infection can still occur.¹
• Refer to an obstetrician for assessment. They may consider continuous aciclovir during the last 4 weeks of pregnancy but this use is unlicensed. Aciclovir reduces viral shedding. This regimen may reduce the risk of clinical recurrence at term.
• Regular viral swabs and culture in late pregnancy do not predict viral shedding at term and are not recommended.
• Aim for vaginal delivery if there are no genital lesions present at the time of labour.
• If there are genital lesions present at the onset of labour, current UK practice is that a Caesarean section is performed. In Holland, vaginal delivery has been permitted in such cases since 1987 with no increase in neonatal infection.⁸
• If the woman has a history of recurrent genital herpes, she should be reassured that the risk of her transmitting the infection to her baby is very small, even if she does have active lesions at delivery.
• If vaginal delivery did take place and there were HSV lesions present, the GP and community midwife should be informed so that they can monitor for signs of neonatal HSV.

The main concern with maternal HSV infection during pregnancy is the risk of neonatal infection as this can lead to severe neurological impairment and death. Neonatal herpes occurs in less than 2 per 100,000 live births.⁹ It usually results from maternal viral shedding during delivery, which may be asymptomatic, but may also rarely be acquired in utero.

It is most likely to occur if the mother develops HSV for the first time during the final trimester.¹ If this is the case, the baby is likely to be delivered before the development of protective maternal antibodies. HSV 2 neonatal infection has a worse prognosis than HSV 1.

Clinical features

• These appear in the neonate 2 to 28 days after delivery.
• Many infected infants present with non-specific signs and without mucocutaneous involvement.
• There is rarely a history of maternal infection.
• The infection tends to follow three different clinical courses. It either:
  • Remains localised to the skin, eyes or mouth. The vesicles are often at the presenting part or at sites of minor trauma, such as a scalp electrode.
  • Causes encephalitis with or without skin, eye or mouth involvement.
  • Results in disseminated infection which can cause jaundice, hepatosplenomegaly and disseminated intravascular coagulation.¹⁰
• (Congenital infection, a consequence of primary infection early in pregnancy, can cause microcephaly, hydrocephalus, chorioretinitis and vesicular skin lesions.)

Treatment of a baby considered to be at risk of neonatal herpes

• Take urine and stool cultures and swabs from the oropharynx, eyes and surface sites for viral culture and typing.
• Intravenous aciclovir is given by many whilst waiting for the results and is the treatment of choice in confirmed infection.
• The child should be isolated.
• Breast feeding is recommended unless the mother has herpetic lesions around the nipples. Aciclovir is excreted in breast milk but there is no evidence of harm.
• Parents should be warned to report any early signs of infection such as poor feeding, lethargy, fever or any suspicious lesions.

• All women should be asked at antenatal booking if they, or their partner, have ever had genital herpes.
• If the male partner has a history of genital HSV and the female is asymptomatic, the couple should be advised not to have sex during a recurrence.
• Avoid sexual promiscuity during pregnancy.
• Condom use throughout pregnancy may help to reduce the risk of HSV infection.
• The risk of HSV-1 infection during oro-genital contact should be discussed and contact avoided if there are oral lesions evident.
• ALL woman should have careful vulval inspection at the onset of labour to look for HSV lesions.
• Anyone with an active oral HSV lesion or herpetic whitlow who comes into contact with the neonate should be advised about the risk of postnatal transmission and avoid direct contact between the lesion and the neonate.⁵