Screening for Down's syndrome.
|a.||combined 1st. trimester screening screens for all chromosomal abnormalities|
|b.||combined 1st. trimester screening screens for Down's syndrome but not neural tube defects|
|c.||it is best done at 12 - 14 weeks|
|d.||it is close to 100% accurate in detecting Down's syndrome|
|e.||it is based on the assay of maternal AFP, HCG and thyroid hormones|
|f.||it shows a unique pattern in the presence on Trisomy 18|
|g.||integrated screening has been the recommended method since April 2010|