indications

Last reviewed 01/2018

Karyotyping:

  • foetal lymphocytes are used for chromosome counting
  • cordocentesis is diagnostic where a chromosomal disorder is suspected e.g. Down's syndrome

Rhesus iso-immunization:

  • analysis of foetal haematocrit and haemoglobin concentration are better predictors of outcome than liquor bilirubin concentraition especially if the cordocentesis is performed in the third trimester
  • normal values are: [Hb] 15 g/l and haematocrit 40-45%
  • a fall in these parameters may indicate the need for an umbilical transfusion of group O, Rh negative blood

Growth retardation:

  • cordocentesis allows the measurement of foetal blood pH, pO2, pCO2, bicarbonate, glucose and lactate

Virus infection:

  • IgM radioimmunoassay of foetal blood allows detection of rubella virus, CMV and toxoplasmosis