Fetal rubella syndrome

Fetal rubella syndrome (FRS) is a spectrum of congenital abnormalities that results from primary maternal infection with the rubella virus. It falls under the TORCH group of infections.

It is important to note that reinfection/reactivation has significantly lower risk of fetal anomalies than compared to primary infection.

Features can include:

The first three were classically termed the Gregg syndrome.

The rate of congenital infection is worst during the 1st trimester (particularly during the first 6 weeks). 

  • maternal rubella specific IgG
  • maternal rubella specific IgM

False positive results of IgM antibodies are common. It must be followed with IgG avidity testing to ensure if the infection is recent or not 7.

Sonographic findings are often not specific and a normal scan cannot absolutely exclude an infection. Features that may be seen include

  • evidence of hydrops fetalis if severe
  • evidence of a congenital cardiac anomaly
  • evidence of intra-uterine growth restriction
  • sub-ependymal cysts: on cranial ultrasound 2
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Article information

rID: 13438
System: Obstetrics
Synonyms or Alternate Spellings:
  • Congenital rubella infection
  • In utero rubella infection
  • Fetal rubella infection
  • Rubella embryopathy

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