A client asks the nurse about the risks and complications associated with prenatal ultrasound.

Which of the following responses by the nurse is accurate?

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.

This finding indicates that the umbilical cord is being compressed, which can reduce the blood flow and oxygen supply to the fetus.

Variable decelerations are abrupt decreases in the fetal heart rate (FHR) that vary in shape, duration, and degree of fall below the baseline.

They are seen as W- or U-shaped waves on the monitor.

Choice B is wrong because fetal hypoxia is not indicated by variable decelerations, but by late decelerations, which are gradual decreases in the FHR that begin after the peak of the contraction and return to baseline after the contraction ends.

Late decelerations are associated with uteroplacental insufficiency, which means that the placenta is not delivering enough oxygen to the fetus.

Choice C is wrong because normal placental function is not indicated by variable decelerations, but by reassuring FHR patterns, such as moderate variability (6 to 25 beats per minute) and accelerations (increases in the FHR above the baseline).

Normal placental function ensures adequate fetal oxygenation and well-being.

Choice D is wrong because adequate fetal oxygenation is not indicated by variable decelerations, but by reassuring FHR patterns, such as moderate variability and accelerations.

Adequate fetal oxygenation means that the fetus is not experiencing hypoxia or distress.

Normal ranges for FHR are 110 to 160 beats per minute at term and 120 to 160 beats per minute before term.

Normal ranges for uterine contractions are 2 to 5 contractions in 10 minutes, lasting less than 90 seconds each.