Screening for Down Syndrome

Note: Down syndrome not Down's syndrome

Based on latest Americal College of O&G guidelines Jan 2007

First Trimester Screening recommended -

Nuchal Translucency(measuring that as a multiple of the median)-in combination with 2 first trimester biochemical markers( free Beta-hCG and PAPP-A(Pregnancy Associated Plasma Protein A)

Patients then stratified into:

1. High-risk group : Offered chorionic villus sampling

2.Low-risk group : no further screening

3. Intermediate group : offered second-trimester screening with biochemical markers( alpha-fetoprotein, unconjugated estriol and inhibin A )

Note : Serum-screening are not as sensitive in twin/triplet gestations

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