Reduction of Risk Potential Q 39

Correct Answer: B. Measures the activity of the fetus

A nonstress test is done to evaluate periodic movement of the fetus. Prenatal non-stress test, popularly known as NST, is a method used to test fetal wellbeing before the onset of labor. A prenatal non-stress test functions in overall antepartum surveillance with ultrasound as a part or component of the biophysical profile. The presence of fetal movements and fetal heart rate acceleration is the most critical feature of the non-stress test.

Option A: It is not done to evaluate lung maturity as in answer A. It is usually estimated by examination of the amniotic fluid, obtained by transabdominal amniocentesis, for lecithin, lecithin/sphingomyelin (L/S) ratio. The Lecithin-to-Sphingomyelin Ratio (L/S ratio) is one of several methods for clinicians to assess fetal lung maturation. This biochemical test was first introduced in the 1970s, where a sample of amniotic fluid was collected via amniocentesis to determine the risk of the neonate developing respiratory distress syndrome (RDS).

Option C: An oxytocin challenge test shows the effect of contractions on fetal heart rate. The oxytocin challenge test (OCT) is a form of antenatal fetal monitoring that is being utilized by obstetricians to assess fetal well-being. Uterine contractions may lower the fetal oxygen supply by decreasing the blood circulation in the intervillous spaces of the placenta.

Option D: Nonstress test does not measure neurological well-being of the fetus. Advances in technology over the past decade have enabled researchers to investigate directly the functional development of the fetal brain through two emerging techniques: functional magnetic resonance imaging (fMRI) and fetal magnetoencephalography (MEG).