Advances in prenatal screening

With the current reduction in obstetric and gynaecological specialists, a pregnant woman's first antenatal visit to the obstetrician or hospital antenatal clinic now frequently occurs after 14 weeks of pregnancy. Therefore the onus for providing prenatal screening and diagnosis advice will increasingly fall to the general practitioner.

It is important that GPs are familiar with the current screening strategies pertinent to the most common chromosome abnormalities (principally Down syndrome) and to the most common genetic syndromes (such as cystic fibrosis).

Currently, combined first trimester nuchal translucency assessment and biochemical screening is the most reliable method for prenatal Down syndrome screening. It provides approximately 90% detection in the hands of appropriately trained and accredited practitioners. Antenatal screening for cystic fibrosis is clearly of benefit in a high risk group. Screening all pregnant women requires considerable genetic counselling and laboratory resources and its routine use is still keenly debated in Australia.