A client who is 15 weeks pregnant comes to the clinic for amniocentesis. Which finding would indicate neural tube defects?

A client who is 15 weeks pregnant comes to the clinic for amniocentesis. Which finding would indicate neural tube defects?

• A. Neural tube defects
• B. Fetal lung maturity
• C. Fetal sex determination
• D. Amniotic fluid color

Answer: (A)

The key idea is that neural tube defects are detected by abnormal markers in amniotic fluid, specifically an elevated alpha-fetoprotein (AFP) level, often accompanied by acetylcholinesterase. AFP is produced by the fetus and normally remains within the fetal circulation; when the neural tube fails to close properly, AFP leaks into the amniotic fluid, signaling an open defect such as anencephaly or open spina bifida. That is why an amniocentesis finding associated with neural tube defects is an abnormal, elevated AFP in the amniotic fluid. The other possible considerations—markers of fetal lung maturity, fetal sex determination, or simply amniotic fluid color—do not indicate neural tube defects.

The key idea is that neural tube defects are detected by abnormal markers in amniotic fluid, specifically an elevated alpha-fetoprotein (AFP) level, often accompanied by acetylcholinesterase. AFP is produced by the fetus and normally remains within the fetal circulation; when the neural tube fails to close properly, AFP leaks into the amniotic fluid, signaling an open defect such as anencephaly or open spina bifida. That is why an amniocentesis finding associated with neural tube defects is an abnormal, elevated AFP in the amniotic fluid. The other possible considerations—markers of fetal lung maturity, fetal sex determination, or simply amniotic fluid color—do not indicate neural tube defects.