Prenatal screening for fetal chromosomal problems (including Down syndrome), is one of the first decisions couples have to make during a pregnancy. Dr. Colin Walsh is an expert at discussing the available options with patients. He recently gave a presentation on this topic to specialist obstetricians and gynaecologists at the New South Wales RANZCOG Fellows Evening in August 2015.
The two best and most popular options for prenatal screening are nuchal translucency (NT) screening and non-invasive maternal testing (NIPT) using fetal DNA (http://www.shoreforwomen.com.au/down-syndrome-chromosomal-screening/). Women may elect to have one or other (or occasionally both) of these testing options.
For most pregnant women, we recommend routine nuchal translucency screening involving a specialist ultrasound and blood test between 11 and 14 weeks. Women who are given a “high-risk” result after the NT screening may elect to proceed to NIPT or CVS/amniocentesis or may prefer no further testing (depending on the actual risk).
For women at “high-risk” of fetal chromosomal problems we recommend NIPT, whereby fetal DNA is extracted from a maternal blood sample after 10 weeks. “High-risk” women include women aged 35 years or over, a family history of chromosomal problems or women who are too late for NT screening (past 14 weeks). We consider it best practice that NIPT testing be combined with an early fetal anatomy scan at 13-14 weeks, to allow early detection of major fetal structural anomalies.