Test Details: PAPP-A (Pregnancy associated plasma protein-A) is a protein produced by the placenta essential for normal fetal development. It increases with gestational age and then rapidly decreases after delivery. The screening is done in the first and second trimester of pregnancy for aneuploidies, which includes trisomy 21 and down syndrome. Decrease in level compared to a normal pregnancy indicates an increased risk for both chromosomal anomalies and adverse pregnancy outcome