Which maternal serum markers are tested in the first trimester maternal serum screening (MSS1)?

In the context of first trimester maternal serum screening, the correct markers to test are PAPP-A (Pregnancy-Associated Plasma Protein A) and β-hCG (beta-human chorionic gonadotropin). These markers are specifically chosen for their importance in assessing the risk of chromosomal abnormalities, such as Down syndrome and trisomy 18.

PAPP-A is a hormone produced by the placenta, and its levels are typically lower in pregnancies affected by chromosomal anomalies. β-hCG is another hormone that rises during pregnancy and is found in elevated levels in certain abnormal pregnancies. The combination of these two markers enables healthcare providers to calculate a risk assessment for these conditions early in the pregnancy, facilitating informed decision-making and further testing if necessary.

Other combinations, such as those involving α-fetoprotein or Inhibin A, are not standard in the first trimester MSS but are used later in pregnancy, specifically in the second trimester maternal serum screening. This highlights how different tests are appropriate at various stages of pregnancy for detecting specific conditions.