Overview & Scope

Genital herpes in pregnancy is important due to the risk of vertical transmission of HSV to the neonate.

Primary maternal infection (especially in the third trimester) carries the highest risk because maternal antibodies are absent.

Recurrent infection carries a much lower risk since maternal antibodies provide partial neonatal protection.

2. Risks to the Fetus/Neonate

• Greatest risk when primary infection occurs in the last 6 weeks of pregnancy (before maternal antibodies develop).

• Neonatal HSV can cause:

  • Skin, eye, mouth lesions

  • CNS involvement (encephalitis)

  • Disseminated infection → high mortality

🔹 3. Antenatal Management

a. Diagnosis

• Confirmed by PCR from genital lesions.

• HSV-1 or HSV-2 typing is useful for counselling.

• Serology may help differentiate primary vs recurrent.

b. Antiviral treatment

• Aciclovir is first-line; safe in all trimesters.

  • Primary infection: aciclovir 400 mg TDS (7–10 days)

  • Recurrent infection: same dose, shorter course

• Valaciclovir may be used (500 mg BD), better compliance.

c. Suppressive therapy

• Start at 32 weeks’ gestation (or 22 weeks if high risk / preterm risk).

  • Aciclovir 400 mg TDS or Valaciclovir 500 mg BD until delivery
    ➤ Reduces viral shedding and lesion recurrence at term.

• Inform neonatal team before delivery.

• If primary maternal infection near delivery → neonatal observation & possible aciclovir prophylaxis.

• Avoid:

  • Fetal scalp electrodes

  • Fetal blood sampling

  • Instrumental delivery if active lesions

🔹 5. Postnatal Advice

• Transmission risk persists postnatally from direct contact with maternal orolabial/genital lesions.

• Advise:

  • Strict hand hygiene

  • Avoid kissing baby if orolabial lesions present

  • Avoid breastfeeding if nipple lesions

🔹 6. Partner Management

• Counsel partners; test and treat if symptomatic.

• Use condoms and avoid sexual contact during symptomatic episodes.

Updated 2024 guidance (joint RCOG/BASHH) provides changes in diagnosis, suppression timing, management of PPROM, and mode of delivery decisions.

Exam Tip (MRCOG/FCPS)