Which pattern of fetal heart rate deceleration begins and ends with the contraction?

• A. Begin after the contraction
• B. Occur randomly outside contractions
• C. Begin at the peak of the contraction and persist beyond its end
• D. Begin and end with the contraction

Answer: (D)

The key idea is understanding how fetal heart rate decelerations relate to contractions. The pattern that begins and ends with the contraction is the early deceleration. It mirrors the timing of the contraction: as the contraction starts, the fetal heart rate dips, and it returns to baseline as the contraction ends. This happens because fetal head compression stimulates the vagal nervous system, producing a transient, symmetric drop in heart rate that tracks with the contraction itself. It’s typically benign and usually requires no intervention.

In contrast, decelerations that start after the contraction point suggest late decelerations, which can indicate uteroplacental insufficiency and may require closer monitoring or intervention. Decelerations that occur randomly and without a consistent relationship to contractions point to variable decelerations, often due to cord compression, and they can occur at any time. A pattern that begins at the peak of the contraction and lasts beyond its end doesn’t fit the hallmark of early decelerations, which are defined by their start and end in concert with the contraction.

So, the pattern that begins and ends with the contraction is the one reflecting early decelerations.