A blood test to assist in diagnosing certain fetal anomalies is called what?

• A. Maternal AFP
• B. Maternal hCG
• C. Maternal estriol
• D. Inhibin A

Answer: (A)

Measuring maternal serum alpha-fetoprotein (AFP) is a screening test used during pregnancy to assess risk for certain fetal anomalies, especially open neural tube defects like spina bifida and anencephaly, and some ventral wall defects. AFP is produced by the fetus and crosses into the mother's blood, so abnormal levels can signal a problem. Elevated AFP in the maternal circulation suggests the possibility of neural tube or ventral wall defects (though dating accuracy, multiple gestations, or maternal factors can affect levels). Low AFP can be associated with other conditions, such as certain chromosomal abnormalities, but is less specific. This test is typically part of a broader maternal serum screening and is used alongside ultrasound and possibly additional tests to evaluate risk, not to diagnose on its own.