Rubella

Question 1

What is the foetal infection rate at these gestations?

<11/40

11-16/40

16-20/40

Answer 1

<11/40 - 90%

11-16/40 - 55%

16-20/40 - 45%

Question 2

Rubella can cause a re-infection in those who are immune via previous infection or immunisation.

This is very rare
What is risk to foetus?

Answer 2

Likely to be a sub-clinical infection

detected with new IgM, and rise in IgG

Risk to foetus presumed low, but no data available

Question 3

Pregnant lady with suspected rubella

What tests to perform?

Answer 3

Rubella IgG on booking bloods. Presence of IgG within 4/52 or rash developing, is likely from old immunisation or infection so is reassuring

Rubella IgM on booking bloods if acute infection suspected or IgG neg. Do not make diagnosis on single IgM pos. Repeat bloods to show IgG seroconversion

Buccal swab for IgM/ PCR

Question 4

Pregnant lady with suspected rubella

What treatment is available?

Answer 4

Risk assess of infection to baby by gestation

USS to see if any congenital abnormality

Offer termination of pregnancy if severely affected foetus

Question 5

What are signs of congenital rubella?

Answer 5

Microcephaly

Sensorineural deafness

Cataracts, retinopathy, microphthalmia

Congenital heart disease

usually pulmonary artery stenosis, PDA

HSM

“blueberry muffin” rash - extra medullary haematopoiesis

Developmental delay