A nurse is explaining the purpose of a Doppler ultrasound blood flow analysis to a client who has intrauterine growth restriction (IUGR).

The nurse should inform the client that this test measures which of the following?

A low level of AFP (<0.5 MoM) in a pregnant woman can indicate that the fetus has a chromosomal abnormality, such as Down syndrome or Edwards syndrome.

This is because these conditions affect the development of the fetal liver, which produces AFP.

Choice A is wrong because neural tube defects, such as spina bifida, are associated with high levels of AFP (>2.5 MoM) in the maternal blood.

This is because AFP can leak from the open spinal canal of the fetus into the amniotic fluid and then into the maternal blood.

Choice C is wrong because maternal weight-related factors do not affect the level of AFP in the maternal blood.

However, they can affect the interpretation of the AFP test results, as the test needs to be adjusted for maternal weight, age, ethnicity, and gestational age.

Choice D is wrong because fetal demise (death) can also cause high levels of AFP in the maternal blood, as the AFP from the dead fetus can leak into the amniotic fluid and then into the maternal blood.

Normal ranges of AFP in pregnant women vary depending on the gestational age and the method of measurement.

Generally, normal levels of AFP are below 10 ng/ml in nonpregnant adults and below 2.5 MoM in pregnant women.

An equivocal CST indicates late decelerations of the FHR with less than 50% of contractions.

This means that the fetus may have some degree of hypoxia or distress, but not enough to warrant immediate delivery.

An equivocal CST may also result from hyperstimulation of the uterus, which can cause excessive contractions and reduce blood flow to the placenta.

Choice B is wrong because late decelerations of the FHR with at least 50% of contractions is a positive CST, which indicates a high risk of fetal death due to hypoxia and is a contraindication to labor.

Choice C is wrong because no late decelerations of the FHR during contractions is a negative CST, which indicates a good fetal wellbeing and tolerance of labor.

Choice D is wrong because variable decelerations of the FHR with or without contractions are not related to uterine activity and may indicate cord compression or other fetal problems.

Variable decelerations are not used to interpret CST results.