Which analysis of maternal serum may predict chromosomal abnormalities in the fetus?

Choice A reason: A daily consumption of alcohol does not necessarily indicate a risk for alcoholism, although it is not recommended for pregnant women. Alcoholism is a chronic disease that involves physical and psychological dependence on alcohol, and it requires more than one criterion to be diagnosed.

Choice B reason: She will not be at risk for abusing other substances as well, unless she has a history or predisposition for substance abuse. Alcohol use during pregnancy does not cause other substance abuse problems, although it may co-occur with them.

Choice C reason: The fetus is not at risk for multiple organ anomalies, unless the mother consumes large amounts of alcohol during the first trimester of pregnancy. This can cause fetal alcohol syndrome (FAS), which is characterized by facial dysmorphia, growth retardation, and intellectual disability. However, FAS is rare and not related to moderate alcohol intake during the second trimester.

Choice D reason: The fetus is placed at risk for altered brain growth, as alcohol can cross the placenta and affect the developing nervous system of the fetus. Alcohol exposure during the second trimester can impair the formation and migration of neurons, leading to reduced brain size and function. This can result in learning difficulties, behavioral problems, and cognitive impairments in the child.

Choice A reason: The NST has no known contraindications, as it is a non-invasive and safe test that does not stimulate uterine contractions or cause fetal distress. It is the most widely used method of antepartum fetal surveillance.

Choice B reason: The NST is not slightly more expensive than the CST, as it requires less time and equipment. The NST usually takes 20 to 40 minutes, while the CST may take up to 2 hours. The NST only needs a fetal monitor, while the CST also needs an intravenous line and oxytocin infusion.

Choice C reason: The NST does not have fewer false-positive results than the CST, as it has a higher rate of nonreactive results that may indicate fetal compromise when there is none. A nonreactive NST is one that does not show at least two accelerations of the fetal heart rate of 15 beats per minute or more lasting 15 seconds or more in a 20-minute period.

Choice D reason: The NST is not more sensitive in detecting fetal compromise than the CST, as it has a lower predictive value for fetal well-being. A reactive NST is one that shows at least two accelerations of the fetal heart rate of 15 beats per minute or more lasting 15 seconds or more in a 20-minute period. However, a reactive NST does not rule out the possibility of fetal hypoxia or acidosis.