What does the characteristic of early decelerations being a "mirror image" indicate?

Early decelerations are characterized as "mirror images" because they align with the timing of uterine contractions. This means that as a contraction begins to rise and peak, the early deceleration occurs at the same time, typically reaching its lowest point when the contraction is at its peak, and then returning to baseline shortly after the contraction ends.

This characteristic reflects a physiological response often related to head compression, which is a normal occurrence during labor as the fetus descends through the birth canal. In contrast, other fetal heart rate patterns, such as variable decelerations or late decelerations, may indicate differing levels of fetal distress or compromise. Since early decelerations are generally considered a benign phenomenon, the fact that they are "mirror images" allows healthcare providers to effectively monitor fetal well-being during labor without immediate concern for acute issues.