Rubella in pregnancy

Definition

• Congenital rubella syndrome (CRS) results from infection of the fetus across the placenta when the pregnant woman has rubella.

Occurrence & epidemiology

Epidemiology

• In the WHO Region of the Americas, rubella and CRS have officially been considered eliminated since 2015.

Aetiopathogenesis

Aetiology and pathogenesis

• Rubella virus is an RNA virus of the family Togaviridae and is usually transmitted by droplets.
• In the first 12 weeks of pregnancy the risk is very high, with damage in up to 90% of fetuses; it decreases markedly in weeks 13 to 16, and from week 20 damage occurs only exceptionally.

Clinical features

Clinical features and complications

• Postnatal rubella is often mild, with nuchal and retroauricular lymphadenopathy and a fine macular rash; up to 50% of infections are asymptomatic.
• The classic Gregg triad comprises defects of the heart (patent ductus arteriosus), eyes (cataract) and ears (sensorineural deafness).
• Further consequences include low birthweight, thrombocytopenic purpura, hepatosplenomegaly, encephalitis, myocarditis and microcephaly; the overall case fatality of CRS is 15–20%.

Diagnosis

• If rubella is suspected in pregnancy, rubella virus PCR from throat swab, urine and blood, IgG avidity testing and immunoblot are used for clarification.
• Prenatally, the virus can be detected by PCR of chorionic villus material or amniotic fluid, and from week 22 additionally by IgM or PCR in fetal blood.

Keep learning in the app

Further reading (selection)

1. Robert Koch Institute, RKI-Ratgeber (German): Röteln

Cross-references