Which type of fetal heart deceleration is caused by uteroplacental insufficiency and is considered the most concerning?

Late deceleration is characterized by a gradual decrease in fetal heart rate that begins after a contraction has started and does not return to baseline until after the contraction has ended. This pattern indicates that the fetus is experiencing some level of stress, often due to uteroplacental insufficiency, where the placenta is not effectively delivering oxygen to the fetus during contractions.

The concern with late decelerations lies in their association with compromised fetal oxygenation, potentially leading to fetal distress. Monitoring this deceleration type is crucial, as it requires prompt evaluation and management to ensure the well-being of the fetus. Recognition and appropriate intervention, such as repositioning the mother or considering delivery, are vital steps when late decelerations are observed during labor.

In contrast, early decelerations are typically benign and occur concurrently with contractions due to fetal head compression. Variable decelerations can occur unpredictably and may be caused by chord compression but do not consistently indicate a significant issue with placental insufficiency. Intermittent decelerations are less defined and could refer to various non-specific dips in heart rate. Therefore, late decelerations are the most concerning when evaluating fetal heart patterns during labor.