Varicella in pregnancy

Definition

• Varicella in pregnancy denotes primary infection of a pregnant woman with varicella-zoster virus (VZV), which is rarely transmitted across the placenta and can endanger both fetus and newborn.

Classification

• Fetal varicella syndrome: it can occur in about 1–2% of varicella cases in pregnant women if the illness occurs between weeks 5 and 24 of gestation.
• Neonatal varicella: it threatens when the mother falls ill within 5 days before to 48 hours after birth, because the infant then receives no protective maternal antibodies.
• Herpes zoster in the mother poses no risk to the unborn child.

Occurrence & epidemiology

Epidemiology

• In Germany, antibodies against VZV were detectable in more than 95% of adults.

Aetiopathogenesis

Aetiology and pathogenesis

• The virus is transmitted by airborne droplet nuclei and by contact with vesicle fluid and is extremely contagious.

Clinical features

Clinical features and complications

• The illness starts with an itchy rash and fever; in adults it is more severe and more often complicated.
• A serious complication is varicella pneumonia, to which pregnant women are particularly susceptible.
• Fetal varicella syndrome shows segmentally distributed skin lesions, neurological damage such as cerebral atrophy, eye damage (microphthalmia, chorioretinitis, cataract) and skeletal anomalies.
• Neonatal varicella runs a very severe course with a case fatality of up to 30%.

Diagnosis

• Direct virus detection is usually done by VZV PCR.
• Immune status is determined by VZV IgG; IgG avidity allows primary infection to be distinguished from herpes zoster.

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Further reading (selection)

1. Robert Koch Institute, RKI-Ratgeber (German): Windpocken (Varizellen), Gürtelrose (Herpes zoster)

Cross-references