HESI Obstetrics (OB) Practice Test

Amniocentesis is a diagnostic procedure that involves taking a sample of amniotic fluid surrounding the fetus. This fluid contains fetal cells and various substances that can be analyzed for chromosomal abnormalities. During this procedure, healthcare providers can perform genetic testing on the cells to identify conditions such as Down syndrome, trisomy 18, and other chromosomal disorders. It is typically performed between 15 and 20 weeks of pregnancy and is considered a highly accurate method for assessing genetic risks.

In contrast, while chorionic villus sampling is also used to detect chromosomal abnormalities, it is performed earlier in the pregnancy and does not involve amniotic fluid. Ultrasound serves primarily as an imaging tool to assess fetal growth and structure, rather than specifically analyzing for chromosomal issues. The non-stress test is utilized to evaluate fetal heart rate and well-being, focusing on the baby's oxygenation and health rather than genetic abnormalities.