A client who is 15 weeks pregnant comes to the clinic for amniocentesis. Which of the following can this test identify?

A client who is 15 weeks pregnant comes to the clinic for amniocentesis. Which of the following can this test identify?

• A. Sex of the fetus
• B. Chromosomal defects
• C. Neural tube defects
• D. Maternal blood type

Answer: (A)

Amniocentesis provides fetal cells from the amniotic fluid that can be cultured and karyotyped to look for chromosomal abnormalities. At 15 weeks, this is a practical time to identify conditions such as trisomies and other chromosomal defects, which is the test’s main clinical purpose. While the fetal sex can be inferred from the genetic material if needed, the primary goal of this procedure is genetic diagnosis, not sex determination. Neural tube defects can be suspected by elevated alpha-fetoprotein (and acetylcholinesterase) in the amniotic fluid, but this is an adjunct to chromosomal analysis rather than the definitive focus of the test. Maternal blood type is determined from the mother's blood, not from amniotic fluid. So, the most direct information obtained from amniocentesis at this gestational age is chromosomal defects.

Amniocentesis provides fetal cells from the amniotic fluid that can be cultured and karyotyped to look for chromosomal abnormalities. At 15 weeks, this is a practical time to identify conditions such as trisomies and other chromosomal defects, which is the test’s main clinical purpose. While the fetal sex can be inferred from the genetic material if needed, the primary goal of this procedure is genetic diagnosis, not sex determination. Neural tube defects can be suspected by elevated alpha-fetoprotein (and acetylcholinesterase) in the amniotic fluid, but this is an adjunct to chromosomal analysis rather than the definitive focus of the test. Maternal blood type is determined from the mother's blood, not from amniotic fluid. So, the most direct information obtained from amniocentesis at this gestational age is chromosomal defects.