This is an option for parents to screen for any risk of fetal chromosomal anomalies (Down, Edwards and Patau syndromes) during the first trimester. OSCAR involves an ultrasound scan and blood tests (BHCG and PAPP-A) performed between 11 to 13 weeks + 6 days to assess the risks of certain genetic disorders or birth defects. These tests may help couples decide if they want to proceed with confirmatory invasive tests.
This test scans for and measures the thickness of the fluid-filled area behind the fetal neck (Nuchal Translucency), following strict adherence to standard NT measurement techniques. Down syndrome babies are usually associated with a thicker-than-normal NT.
An absence of a fetal nasal bone, along with a thickened NT, is associated with a higher risk of Down syndrome.
In addition to increasing maternal age and thickened NT, an increased maternal serum BHCG and decreased PAPP-A concentration are also associated with an increased risk of Down syndrome.
Normal nasal bone and nuchal translucency (Low risk of Down Syndrome)
Absent nasal bone and thicken nuchal translucency (High risk of Down Syndrome)