Late deceleration in fetal hea rate monitoring is suggestive of: March 2012
**Core Concept**
Late deceleration in fetal heart rate monitoring refers to a deceleration in the fetal heart rate that occurs after the peak of a uterine contraction. This phenomenon is associated with fetal distress and potential compromise of placental perfusion.
**Why the Correct Answer is Right**
Late decelerations are caused by a decrease in placental blood flow during uterine contractions. This can be due to a variety of factors, including umbilical cord compression, placental abruption, or maternal hypotension. The decrease in placental blood flow leads to a reduction in fetal oxygen and nutrient delivery, resulting in a decrease in fetal heart rate. The mechanism is thought to be mediated by the release of vasoactive substances, such as endothelin and thromboxane, which cause vasoconstriction and reduce placental blood flow.
**Why Each Wrong Option is Incorrect**
**Option A:** Early decelerations are associated with fetal head compression and are typically seen in the presence of a normal fetal heart rate baseline. They are not indicative of fetal distress.
**Option B:** Variable decelerations are associated with umbilical cord compression and are typically seen in the presence of a normal fetal heart rate baseline. While they can be an indicator of fetal distress, they are not as specific as late decelerations.
**Option C:** Accelerations are associated with fetal well-being and are typically seen in the presence of a normal fetal heart rate baseline. They are not indicative of fetal distress.
**Clinical Pearl / High-Yield Fact**
Late decelerations are a critical indicator of fetal distress and should prompt immediate evaluation and intervention.
**Correct Answer: B. Variable decelerations are associated with umbilical cord compression and are typically seen in the presence of a normal fetal heart rate baseline. While they can be an indicator of fetal distress, they are not as specific as late decelerations.