Herpes Simplex Infection in Pregnancy

Last updated 03.11.12

 

Index

 

Definition

-  Genital infection during pregnancy with Herpes Simplex Virus (HSV)

-  Primary infection: recently acquired infection (nil Abs to HSV1 or HSV2)

-  Non-primary infection: recently acquired infection (w Ab to alternate HSV)

-  Ie: previous infection w one type & new infection w other

-  Recurrence: previously acquired infection (w Abs to same type HSV1 or HSV2)

-  First episode: fist clinical episode (may be any of above)

 

Features

-  Genital lesions from HSV effect 20% people by 32yrs old

-  Females > males

-  Transmission between adults via direct contact

-  May shed virus when asymptomatic

-  HSV1: orogenital sex

-  HSV2: vaginal or anal sex

-  Vertical transmission from mother to fetus

-  Infection usually occurs at or near time of delivery

-  57% risk if primary infection

-  25% risk if non-primary infection

-  0.05% risk if previous infection but no current S/S

-  0.25-3% risk if previous infection & lesions at delivery

 

Causes

-  HSV1

-  Typical cause of orolabial infection

-  35% of cases in Australia

-  HSV2

 

Associated S/S

-  Latent phase for 2-20/7 post exposure

-  +/- Prodrome

-  Flu like S/S

-  Local tingling, irritation, pruritis &/or pain

-  Lesions on genitals, anal area, buttocks &/or thighs

-  May persist up to 3 weeks

-  Pruritic erythematous plaques --> clusters of vesicles

-  Progress to painful, sloughy, shallow ulcers w irregular margins

 

Complications

-  Maternal

-  Meningitis (HSV2)

-  Encephalitis (HSV1)

-  Bells palsy (HSV1)

-  Erythema multiform

-  Steven-Johnson syndrome

-  Disseminated infection: hepatitis, pneumonia

-  Miscarriage if vertical transmission <20/40

-  Preterm delivery

-  Fetal

-  Neonatal herpes

-  Skin lesions, chorioretinopathy, microcephaly, hydrocephaly

 

Ix

-  Swab MCS: HSV1 or HSV2

-  +/- PCR

-  Serology

-  IgG: HSV1 or HSV2

-  High titre ass w lower risk & lesser severity of neonatal infection

-  Does not DDx site of infection

-  False negatives & positives

-  Usually takes 2-6 weeks post infection

-  Some pts do not seroconvert

-  Seroreversion may occur

 

Mx

-  If in labour & active lesions offer LUSCS

-  Reduced vertical transmission

-  Prophylaxis

-  Indicated if

-  Recurrent episodes

-  First or second trimester first episode

-  Aciclovir 400mg PO BD

-  Third trimester (+/- >36/40)

-  Reduces clinical reoccurrence & need for LUSCS

-  No difference in neonatal outcome

-  Treatment

-  First episode Aciclovir 200mg PO 5 times per day 5/7

-  If severe or immunosupressed IV 5mg/kg 8/24

-  If in 1st or 2nd trimester prophylaxis post treatment

-  If in 3rd trimester treat then aim for LUSCS

-  Recurrent episode

-  Avoid scalp electrodes & instrumental delivery

-  Baby Care

-  New born examination

-  Neonatal conjunctival, throat & rectal cultures at 48hrs in all pts w prev Hx of HSV unless nil recurrence during the pregnancy

-  If symptomatic or positive cultures

-  Aciclovir

-  OR watch baby closely: daily temp & R/V for skin lesions +/- FBE, LFT, Coags

 

 

 

References

 

New Zealand Herpes Foundation, www.herpes.org.nz