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What conditions can elevated alpha-fetoprotein levels during pregnancy suggest?

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Elevated levels of alpha-fetoprotein (AFP) in maternal blood during the second trimester are primarily associated with neural tube defects in the fetus, such as spina bifida and anencephaly.312

However, high AFP levels do not always indicate a defect. Other factors can cause elevated readings, including:

Multiple pregnancies (e.g., twins or triplets)
Underestimation of gestational age
Fetal death3

Because these screenings are associated with a high rate of false-positive results, medical professionals typically use ultrasound to investigate further and rule out these alternative causes. If results remain concerning, more specific diagnostic procedures, such as amniocentesis to analyze the amniotic fluid, may be performed.312

It is important to approach these findings with the understanding that screening tests are designed to assess risk rather than provide a definitive diagnosis, and parents may benefit from consulting with a genetic counselor to interpret the results and discuss potential next steps.2