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HSV genital infection and pregnancy

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

4-5% of ante-natal patients in the UK have a history of genital herpes. 80% is a result of infection with herpes simplex type II virus.

About 50% of babies will be infected with herpes simplex if the mother has active cervical lesions.

The incidence of recurrence increases towards term.

Diagnosis is as in non-pregnant women. Viral cultures are taken (weekly) from 36 weeks gestation from the cervix of all women with a history of genital herpes (1)

If genital herpes infection during pregnancy then consult obstetric advice regarding management (1)

The risk of neonatal transmission is low if genital herpes occurs in the first and second trimester (2,3,4)

However, patients with genital herpes after 34 weeks of gestation and those who have not completed at least 4 weeks of acyclovir therapy before delivery are at a high risk of transmitting the infection to the neonates

  • some state caesarean delivery is indicated for such cases, but it does not completely eliminate the risk (4)
  • some state the best policy would be to continue acyclovir till delivery and perform cesarean section at full term (5)
    • elective cesarean delivery is especially indicated if active HSV lesions are present during or within 2 weeks of labour (5)

  • aciclovir in pregnancy (2,3,4)

    • safety of this drug in pregnancy has not been definitively established but available data do not suggest major birth defects due to acyclovir
      • benefits much outweigh the risk

    • women with symptomatic primary or first-episode HSV infection during pregnancy
      • antiviral (acyclovir 400 mg tid for 7-14 days) therapy is recommended for

    • symptomatic recurrent HSV
      • should be treated with acyclovir 400 mg tid for 5 days

    • for women with frequent or severe recurrences, especially after the first trimester
      • daily suppressive therapy (acyclovir 400 mg tid) from 36 weeks of gestation till delivery may be indicated

  • NICE state that (6)
    • maternal herpes simplex women with primary genital herpes simplex virus (HSV) infection occurring in the third trimester of pregnancy should be offered planned CS because it decreases the risk of neonatal HSV infection
    • pregnant women with a recurrence of HSV at birth should be informed that there is uncertainty about the effect of planned CS in reducing the risk of neonatal HSV infection. Therefore, CS should not routinely be offered outside a research context

Reported side-effects of nausea and abnormal liver function test (LFT) are more commonly seen after intravenous rather than oral administration. Therefore, treatment usually does not require LFT monitoring, although it can on rare occasions cause rash.Notes:

  • neonatal infection is uncommon in cases of recurrent genital herpes - this is because of relatively lower concentration and shedding of the virus and the passive immunity acquired by the fetus from the mother

Consult the appropriate summary of product characteristics before prescribing any of the drugs mentioned.


  1. Prescriber 2005; 16(6):14-24.
  2. Fatahzadeh M, Schwartz RA. Human herpes simplex virus infections: Epidemiology, pathogenesis, symptomatology, diagnosis, and management. J Am Acad Dermatol 2007;57:737-63; quiz 764-6
  3. Brown ZA, Gardella C, Wald A, Morrow RA, Corey L. Genital herpes complicating pregnancy. Obstet Gynecol 2005;106:845-56
  4. Martinez V, Caumes E, Chosidow O. Treatment to prevent recurrent genital herpes. Curr Opin Infect Dis 2008;21:42-8.
  5. Nath AK, Thappa DM. Newer trends in the management of genital herpes. Indian J Dermatol Venereol Leprol. 2009 Nov-Dec;75(6):566-74.
  6. NICE (April 2019). Caesarian Section

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