What biochemical marker screen finding would be most consistent with Down syndrome in a pregnant patient?

The correct answer is rooted in understanding the biochemical markers that are commonly evaluated in the first and second trimesters of pregnancy to assess the risk of certain chromosomal anomalies, including Down syndrome (trisomy 21).

For Down syndrome, the characteristic biochemical marker profile includes low levels of alpha-fetoprotein, elevated levels of human chorionic gonadotropin, low levels of estriol, and increased levels of inhibin A.

• Low alpha-fetoprotein is indicative of potential chromosomal abnormalities and is one of the first markers dropped in the context of Down syndrome.
• Elevated human chorionic gonadotropin is often associated with the increased production of this hormone in pregnancies complicated by Down syndrome.
• Low estriol levels correlate with this condition, reflecting lower fetal wellbeing, as estriol is produced by both the placenta and the fetus.
• High levels of inhibin A further enhance the screening result for Down syndrome, as this hormone also has been shown to be elevated when this chromosomal condition is present.

This combination of markers presents a clear picture that healthcare providers can use to appropriately counsel expectant mothers about their risks and the need for further diagnostic testing. The other options do not align with this well-established biochemical profile associated with Down