Genital Herpes in Pregnancy

This document is mainly based on the Royal College of General Practitioners (RCGP)¹ and genitourinary medicine (GUM) guidance.² It should be read alongside the main, separate article Genital Herpes Simplex.

Aetiology, epidemiology, transmission, presentation, complications and differential diagnosis of infection with herpes simplex virus (HSV) 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 (primary infection) or a recurrence? See table below.
2. What trimester of pregnancy is the woman in?

Management of first episode

1st and 2nd trimester presentation

• Refer to a genitourinary medicine (GUM) clinic- same day referral if possible.
• Confirm the diagnosis (take viral swabs if not seen on the same day by a genitourinary department). Diagnosis is by viral culture or polymerase chain reaction.
• Manage symptomatically according to the patient's need. Follow the same procedure as that with primary infection in a non-pregnant person, as outlined in the main article.
• Use of antivirals in pregnancy:
  • Aciclovir has a good safety record in pregnancy (although not licensed for this use). It should be used with caution if <20 weeks' gestation, but there is no evidence of teratogenicity.
  • The dose in pregnancy is either 200 mg five times daily or 400 mg three times daily.³
  • Start within 5 days of onset of symptoms, or if new lesions are still forming.
  • Disseminated infection requires treatment with aciclovir.
  • Valacyclovir has also been used in pregnancy.⁴
• Inform other people involved in the woman's antenatal care (midwife, obstetrician).
• Aim for a vaginal delivery but consider offering Caesarean section.
• Consider daily suppressive aciclovir from 36 weeks - to reduce the likelihood of herpes simples virus (HSV) lesions at term and the need for Caesarean section.³ A dose of aciclovir 400 mg three times daily may be appropriate because of the altered pharmacokinetics of the drug in late pregnancy.²
• 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.

• Refer, diagnose and treat as for 1st trimester, and also:
• This scenario 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.³
• Refer to an obstetrician.
• Serology (HSV antibody testing) can be useful, to help distinguish primary and secondary infection and to type the virus. These may influence management decisions.
• A Caesarean section is recommended for women who develop primary genital herpes within 6 weeks of delivery.³ (The woman can still be shedding the virus at delivery, even if there are no visible lesions.)
• Caesarean section for the prevention of neonatal herpes has not been evaluated in randomised controlled trials and may not confer complete protection.
• If the baby is delivered vaginally, avoid rupture of membranes and invasive procedures (which increase the risk of neonatal herpes). Consider intravenous aciclovir for the mother intrapartum and for the neonate.
• Inform the paediatrician.

Management of recurrent infection

Recurrent genital herpes is associated with a much smaller risk of neonatal herpes.³ One study reported a transmission rate of 3%⁵ while another study reported a rate of 0%.⁶
• Confirm the diagnosis.
• Maternal antibodies will give some protection to the baby but neonatal infection can still occur.¹
• Antiviral treatment is not usually indicated.
• Aim for vaginal delivery if there are no genital lesions present at the time of labour.
• Refer to an obstetrician for assessment. They may consider continuous aciclovir during the last 4 weeks of pregnancy, to 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.
• If there are genital lesions present at the onset of labour, current UK practice is that a Caesarean section be performed. In the Netherlands, vaginal delivery has been permitted in such cases since 1987 with no increase in neonatal infection.⁷
• If the woman has a history of recurrent genital herpes, she should be reassured that the risk of 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 herpes simplex viral (HSV) infection during pregnancy is the risk of neonatal infection as this can lead to severe neurological impairment and to death. Neonatal herpes occurs in fewer than 2 per 100,000 live births.⁸ 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 nonspecific signs and without mucocutaneous involvement.
• There is rarely a history of maternal infection.
• The infection may follow three different clinical courses:
  1. Localised infection - skin, eyes or mouth. The vesicles are often at the presenting part or at sites of minor trauma, such as a scalp electrode.
  2. Encephalitis with or without skin, eye or mouth involvement.
  3. Disseminated infection which can cause jaundice, hepatosplenomegaly and disseminated intravascular coagulation.⁹

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 herpes simplex virus (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 orogenital contact should be discussed and contact avoided if there are oral lesions evident.
• All women 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.

1. Sexually Transmitted Infections in Primary Care, Royal College of General Practitioners (2006)
2. Management of genital herpes, British Association for Sexual Health and HIV (2007)
3. Management of genital herpes in pregnancy, Royal College of Obstetricians and Gynaecologists (2007)
4. Anzivino E, Fioriti D, Mischitelli M, et al; Herpes simplex virus infection in pregnancy and in neonate: status of art of Virol J. 2009 Apr 6;6:40. [abstract]
5. Brown ZA, Benedetti J, Ashley R, et al; Neonatal herpes simplex virus infection in relation to asymptomatic maternal infection at the time of labor. N Engl J Med. 1991 May 2;324(18):1247-52. [abstract]
6. Prober CG, Sullender WM, Yasukawa LL, et al; Low risk of herpes simplex virus infections in neonates exposed to the virus at the time of vaginal delivery to mothers with recurrent genital herpes simplex virus infections. N Engl J Med. 1987 Jan 29;316(5):240-4. [abstract]
7. van Everdingen JJ, Peeters MF, ten Have P; Neonatal herpes policy in The Netherlands. Five years after a consensus conference. J Perinat Med. 1993;21(5):371-5. [abstract]
8. Tookey P, Peckham CS; Neonatal herpes simplex virus infection in the British Isles. Paediatr Perinat Epidemiol. 1996 Oct;10(4):432-42. [abstract]
9. Kimberlin DW, Whitley RJ; Neonatal herpes: what have we learned. Semin Pediatr Infect Dis. 2005 Jan;16(1):7-16. [abstract]

• Hollier LM, Wendel GD; Third trimester antiviral prophylaxis for preventing maternal genital herpes simplex virus (HSV) recurrences and neonatal infection. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD004946. [abstract]
• Sen P, Barton SE; Genital herpes and its management. BMJ. 2007 May 19;334(7602):1048-52.
• Herpes Virus Association