A nurse is explaining the purpose of a Contraction Stress Test (CST) to a pregnant client.

What does the CST aim to assess?

This is because a nuchal translucency ultrasound measures the amount of fluid behind the baby’s neck in the first trimester of pregnancy, which can indicate the risk of having a chromosomal condition like Down syndrome.

Some possible explanations for the other choices are:

Choice A is wrong because fetal growth and development are not directly related to the nuchal translucency measurement.

Fetal growth and development are assessed by other parameters such as crown-rump length, biparietal diameter, abdominal circumference, etc.

Choice B is wrong because blood flow in the umbilical cord is not measured by the nuchal translucency ultrasound.

Blood flow in the umbilical cord is assessed by Doppler ultrasound, which evaluates the resistance and velocity of blood flow in the umbilical artery and vein.

Choice D is wrong because structural abnormalities in the baby’s organs are not detected by the nuchal translucency ultrasound.

Structural abnormalities in the baby’s organs are diagnosed by a detailed anatomy scan, which is usually performed in the second trimester of pregnancy.

The normal range for nuchal translucency is between 1 mm and 3 mm.

A measurement above 3 mm is considered increased and may indicate a higher risk of chromosomal or genetic conditions.

However, a nuchal translucency ultrasound is a screening test and not a diagnostic test, so it does not confirm or rule out any condition.

It only provides a probability based on statistical calculations.

Therefore, further testing may be recommended if the nuchal translucency measurement is increased or if other risk factors are present.

This is because AFP levels vary according to the gestational age of the fetus, and reporting them as multiples of the median (MoM) allows for a standardized comparison.

Choice B is wrong because AFP results do not differentiate between neural tube defects and chromosomal abnormalities.

They only indicate an increased risk for these conditions, which need further testing to confirm.

Choice C is wrong because AFP results do not assess the risk of fetal demise or multiple gestation.

They only measure the amount of AFP in the maternal blood, which can be affected by various factors such as maternal weight, race, diabetes, and fetal anomalies.

Choice D is wrong because AFP results are reported as MoM regardless of factors such as maternal weight and race.

These factors are taken into account when calculating the MoM value, which adjusts for the expected variation in AFP levels among different populations.

Normal ranges for AFP MoM vary depending on the laboratory and the method used, but generally they are between 0.5 and 2.52.

Values above or below this range may indicate an increased risk for certain fetal conditions or complications.