Compared with contraction stress test (CST), nonstress test (NST) for antepartum fetal assessment:

Choice A reason: Intense abdominal pain is the most prevalent clinical manifestation of abruptio placentae, as it indicates the detachment of the placenta from the uterine wall and the bleeding into the uterine muscle. The pain can be localized or diffuse, and it can be constant or intermittent. The pain can also radiate to the back or the shoulder.

Choice B reason: Cramping is not the most prevalent clinical manifestation of abruptio placentae, as it is not specific to the condition. Cramping can occur in normal pregnancy or in other complications such as preterm labor, infection, or cervical insufficiency.

Choice C reason: Uterine activity is not the most prevalent clinical manifestation of abruptio placentae, as it is not specific to the condition. Uterine activity can occur in normal pregnancy or in other complications such as preterm labor, infection, or placenta previa.

Choice D reason: Bleeding is not the most prevalent clinical manifestation of abruptio placentae, as it may or may not be present. Bleeding can be concealed or revealed, depending on the location and extent of the placental separation. Concealed bleeding occurs when the blood is trapped behind the placenta and does not exit the vagina. Revealed bleeding occurs when the blood passes through the cervix and exits the vagina.

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.