Herpes Simplex Virus

Herpes Simplex Virus (HSV) in Pregnancy

Contributor: Andrew Lane, MD Last Update: 04/24/2023

Background

Virus: double stranded DNA virus
- Historically: HSV-1 = oral infection, HSV-2 = genital infection
- Currently: HSV-1 = oral or genital infection, HSV-2 = genital infection
Transmission: direct contact through mucosa, abraded skin, leading to a lifelong infection
Incubation: 2-12 days
Prevalence: 50M cases in the US (1 in 5 women)
Pregnancy incidence: ~ 2% of pregnant women will acquire a new infection during pregnancy, 75% of those with recurrent outbreaks will experience a recurrence during pregnancy
Differential diagnosis: primary syphilis (painless, indurated clean based ulcer (chancre)), chancroid (deep, undermined, purulent ulcers, may be associated with painful lymphadenitis), drug eruptions, Behcet's disease

Management

Goal: prevent acquisition of a new infection during pregnancy and avoid exposure of the neonate to lesions and viral shedding during delivery

Initial Visit
- All pregnant women should be asked if they have a history of genital HSV
- Routine serologic testing is not recommended
- Encourage partner to have serologic testing with his provider of the health department
  - Seroconcordant couple – partner already infected, no further action
  - Serodisconcordant couple- long term suppressive therapy may decrease the risk of transmission to the uninfected partner

Subsequent visits
- Treat all outbreaks
- Suppressive therapy by 36 weeks
  - Decreases the risk of recurrence at delivery by 75% and C/S rate by 40%

Diagnosis - requires confirmation with BOTH serology and virology (unroof vesicle with sterile needle)

Virology Result (PCR)*	Serology Result**		Classification	Neonatal Transmission at Time of Delivery***
Virology Result (PCR)*	HSV-1 IgG	HSV-2 IgG	Classification	Neonatal Transmission at Time of Delivery***
HSV-1 +	-	-	Primary HSV-1	Primary: 50% Non primary 1st ep: 33% Recurrence: < 4%
	-	+	Non-primary, 1st episode HSV-1
	+	-/+	Recurrent HSV-1
HSV-2 +	-	-	Primary HSV-2
	+	-	Non-primary, 1st episode HSV-2
	-/+	+	Recurrent HSV-2

*PCR preferred by CDC (only 80% primary, 40% recurrent will test + with culture)

**CDC no longer recommends IgM as it can be positive in recurrences and recent infections can cause false negative results, consider repeating IgG in several weeks to look for seroconversion if concern for recent infection

***C/S lowers this risk (1.2%), but can’t completely prevent it

Treatment

Indication	Valacyclovir*	Acyclovir*
Primary or non-primary 1st episode	1 g BID x 7-10 days**	400 mg TID x 7-10 days**
Recurrent episode	500 mg BID x 3 days, 1 g QD x 5 days	800 mg TID x 2 days 800 mg BID x 5 days,
Suppression	500 mg BID from 36 wks - delivery	400 mg TID from 36 wks - delivery
Severe, disseminated disease	Acyclovir 5-10 mg/kg IV q 8 hrs x 2-7 days, then oral therapy for a primary infection for a total treatment of 10 days

*Both are safe in pregnancy and breastfeeding; valacyclovir may improve compliance, acyclovir is often less expensive out of pocket

**May extend treatment if healing is incomplete after 10 days, consider continuing therapy until delivery if in 3rd trimester

Delivery Planning*

Clinical Scenario	Recommendation
Active lesions or prodromal symptoms at time of delivery	ACOG: C/S
Active lesions and ROM at term or delivery is otherwise indicated	ACOG: C/S despite duration of ROM**
Active lesions of back, buttocks, thigh	ACOG: SVD, cover all lesions with occlusive dressing, good hand hygiene
Primary or non-primary 1st ep. in 3rd trimester, no lesions/symptoms at time of delivery	ACOG: C/S may be offered due to the possibility of prolonged viral shedding
PPROM with lesions/symptoms	ACOG: weigh risks of prematurity against risk of neonatal HSV, if expectant management is pursued, treat with acute and then suppressive therapy, treat PPROM as usual, deliver for usual indications, repeat exam when delivery is imminent with C/S for lesions/symptoms or consider C/S if outbreak was primary or non-primary 1st ep. in 3rd trimester
Breast feeding	ACOG: encouraged as long as there are no breast lesions, good hand hygiene

*All patients with known HSV, regardless of timing and route of delivery, must hav a speculum exam to document any lesions at time of admission for delivery; attempts should be made to avoid invasive monitoring when possible

**No evidence that there is a duration of ROM beyond which the fetus would not benefit from C/S

***Mean duration of untreated viral shedding = 15 days

REFERENCES

ACOG. Practice Bulletin #220: Management of Genital Herpes in Pregnancy. 2020.
CDC. STD Treatment Guidelines 2021.

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Herpes Simplex Virus

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