Review Question - QID 105265

Early decelerations in fetal heart rate monitoring are indicative of fetal head compression.

Recall the different types of decelerations: early, late and variable. Any deceleration is a decrease in the heart rate of the fetus below its baseline. Early decelerations are slowing of the fetal heart rate in a pattern that is exactly synchronous with the contraction. They indicate fetal head compression within the birth canal. Late decelerations are slowing of the heart rate that occur towards the end of the contraction cycle. They signify utero-placental insufficiency. Finally, variable decelerations are varied in onset, duration and depth. They may occur between or with contractions and they have an abrupt onset and rapid recovery. These types of decelerations represent umbilical cord compression.

Bailey discusses intrapartum fetal monitoring. Continuous electronic fetal monitoring has been shown to reduce the incidence of neonatal seizures, but there has been no beneficial effect in decreasing cerebral palsy or neonatal mortality. The key elements include assessment of baseline heart rate, presence or absence of variability, and interpretation of periodic changes.

Sweha et al. discuss interpretation of the electronic fetal heart rate during labor. Although detection of fetal compromise is one benefit of fetal monitoring, there are also risks, including false-positive tests that may result in unnecessary surgical intervention. Fetal heart rate patterns are classified as reassuring, nonreassuring or ominous. Nonreassuring patterns such as fetal tachycardia, bradycardia and late decelerations with good short-term variability require intervention to rule out fetal acidosis.

Hamilton and Warrick discuss electronic fetal surveillance. Basic technology in electronic fetal monitors has changed little over hte past decades. However, the clinical response to this monitoring has changed substantially. Furthermore, there has been increased awareness that environmental and human factors can impair clinical judgement, resulting in delayed intervention and birth injury.

Image A represents the tracing of an early deceleration.
Illustration A shows an example of a late deceleration. Illustration B shows an example of a variable deceleration.

Incorrect Answers:
Answers 2 and 4: Late decelerations would be indicative of utero-placental insufficiency, a potentially dangerous situation for the fetus.
Answer 3: Variable decelerations are indicative of cord compression.
Answer 5: Fetal bradycardia would be indicative of congenital heart block.