"My doctor told me that I will have a blood test in my second trimester of pregnancy that can detect if my baby has problems. This test is called maternal serum alpha-fetoprotein screening. What is maternal serum alpha-fetoprotein screening? What can it tell me?"

Maternal serumalpha-fetoprotein (MSAFP) screening is a blood test that looks at certain proteins to screen for certain types of birth defects like neural tube defects (such as spina bifida) and Down syndrome in pregnancy. This test is routinely offered to all pregnant women.

A genetic counselor plays an important role in helping expectant mothers and their families understand the difference between a screening and a diagnostic test. MSAFP is a screening test, so further testing may be needed to confirm a diagnosis. If the results from the MSAFP screening are not within the normal range, the genetic counselor can explain what additional testing/procedures (including ultrasound and amniocentesis) may be performed to diagnose the problem and provide support for the parents. Genetic counselors can help families understand the role that MSAFP screening plays in detecting possible birth defects, as well as the risks, benefits and limitations of the additional testing.

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