What defines late decelerations?

Late decelerations are defined by their characteristic timing and shape in relation to uterine contractions. The key feature is that they occur after the peak of a contraction, with the nadir (the lowest point of the deceleration) happening later than the peak. Additionally, late decelerations are characterized by a gradual decrease in fetal heart rate that persists for more than 30 seconds from the onset of the deceleration to its lowest point.

This information is crucial for identifying fetal distress and determining whether the fetus might be experiencing uteroplacental insufficiency. Recognizing this can help healthcare providers make timely decisions regarding management during labor. The gradual nature of the decline is also significant because it differentiates late decelerations from other types of decelerations that may have different implications for fetal well-being.