Maternity Nursing: Intrapartum Q 2
A nurse is monitoring a client in labor. The nurse suspects umbilical cord compression if which of the following is noted on the external monitor tracing during a contraction?
A. Early decelerations
B. Variable decelerations
C. Late decelerations
D. Short-term variability
Correct Answer: B. Variable decelerations
Variable decelerations occur if the umbilical cord becomes compressed, thus reducing blood flow between the placenta and the fetus. Pressure on the cord initially occludes the umbilical vein, which results in an acceleration (the shoulder of the deceleration) and indicates a healthy response. This is followed by occlusion of the umbilical artery, which results in a sharp downslope. Finally, the recovery phase is due to the relief of the compression and the sharp return to the baseline, which may be followed by another healthy brief acceleration or shoulder
Option A: Early decelerations result from pressure on the fetal head during a contraction. This type of deceleration has a uniform shape, with a slow onset that coincides with the start of the contraction and a slow return to the baseline that coincides with the end of the contraction. Thus, it has the characteristic mirror image of the contraction
Option C: Late decelerations are an ominous pattern in labor because it suggests uteroplacental insufficiency during a contraction. A late deceleration is a symmetric fall in the fetal heart rate, beginning at or after the peak of the uterine contraction and returning to baseline only after the contraction has ended. The descent and return are gradual and smooth. Regardless of the depth of the deceleration, all late decelerations are considered potentially ominous.
Option D: Short-term variability refers to the beat-to-beat range in the fetal heart rate. The FHR is under constant variation from the baseline. This variability reflects a healthy nervous system, chemoreceptors, baroreceptors, and cardiac responsiveness. Prematurity decreases variability; therefore, there is little rate fluctuation before 28 weeks. Variability should be normal after 32 weeks.