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 a contraindication for the Contraction Stress Test (CST) because it increases the risk of infection and umbilical cord prolapse.

A CST is a test that measures the baby’s heart rate during uterine contractions induced by oxytocin or nipple stimulation.

Choice A is wrong because gestational diabetes is not a contraindication for the CST.

It is a condition that affects how the body processes glucose during pregnancy and may cause complications such as macrosomia (large baby), hypoglycemia (low blood sugar) or preeclampsia (high blood pressure and protein in urine).

Choice B is wrong because mild preeclampsia is not a contraindication for the CST.

It is a condition that causes high blood pressure and protein in urine after 20 weeks of pregnancy and may affect the placenta, kidneys, liver or brain.

Choice C is wrong because preterm labor is a relative contraindication for the CST, not an absolute one.

It means that the test may be performed if the benefits outweigh the risks, but it should be avoided if possible because it may trigger early labor or delivery.

Preterm labor is defined as regular uterine contractions with cervical changes before 37 weeks of pregnancy.

Normal ranges for blood pressure are below 120/80 mmHg, for glucose are 70-100 mg/dL (fasting) or below 140 mg/dL (2 hours after eating), and for protein in urine are less than 300 mg/24 hours.