Feature Article

Prenatal screening and diagnosis

Ian Jones, Alister Jones



Noninvasive prenatal screening tests are available to identify fetuses at increased risk of chromosome abnormalities such as trisomy 21. The identification of fetuses at increased risk of these conditions allows women to then be offered diagnostic testing.

Key Points

  • Prenatal screening is voluntary. Patients should receive counselling about what a screening program can offer.
  • Several noninvasive screening options, including nuchal translucency screening and serum analyte testing, are available during the antenatal period.
  • Invasive diagnostic tests include chorionic villus sampling, amniocentesis and fetal blood sampling.
  • Maternal age remains a very important predictor of fetal abnormalities.
  • First-trimester screening provides a greater accuracy of results than the second-trimester quadruple test.