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

• A. Placental previa
• B. Fetal heart rate
• C. Chromosomal defects
• D. Maternal blood type

Answer: (C)

Amniocentesis is used to diagnose chromosomal abnormalities in the fetus by analyzing fetal cells shed into the amniotic fluid. By obtaining a sample of this fluid, clinicians can perform karyotyping or more advanced genetic testing to detect abnormalities in chromosome number or structure, such as trisomies or deletions. This is exactly what chromosomal defects refer to in the context of prenatal testing.

Placental previa, the placenta covering the cervix, is assessed with ultrasound to visualize placental location, not by analyzing amniotic fluid. Fetal heart rate is monitored via ultrasound or Doppler, not through amniocentesis. Maternal blood type is determined from maternal blood samples, not from fetal cells in the amniotic fluid.