End-diastolic velocity (EDV) in pregnancy refers to the velocity of blood flow in a specific artery, usually the umbilical artery, at the end of the heart's relaxation phase (diastole). It's a key measurement obtained during Doppler ultrasound to assess fetal well-being and placental function.
Here's a breakdown:
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Doppler Ultrasound: This specialized ultrasound technique measures blood flow velocity.
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Umbilical Artery: This artery carries deoxygenated blood from the fetus to the placenta. Analyzing its blood flow provides insights into the placental resistance.
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Diastole: The phase of the heart cycle when the heart muscle relaxes and the chambers fill with blood.
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End-Diastolic Velocity (EDV): The speed of blood flowing through the umbilical artery at the very end of diastole. A healthy pregnancy typically has a positive EDV, indicating continuous blood flow.
Significance of EDV
The EDV, along with other Doppler measurements like Peak Systolic Velocity (PSV) and calculations like the Systolic/Diastolic (S/D) ratio, Resistance Index (RI), and Pulsatility Index (PI), helps doctors assess:
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Placental Resistance: Lower EDV (or absent/reversed EDV) suggests increased resistance in the placental blood vessels, potentially restricting blood flow and oxygen delivery to the fetus.
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Fetal Well-being: Abnormal EDV can indicate fetal distress or growth restriction.
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Pregnancy Complications: It can help identify and manage complications like pre-eclampsia.
Interpretation of EDV Results
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Normal EDV: Indicates healthy placental function and adequate blood flow to the fetus.
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Reduced EDV: May suggest placental insufficiency, requiring closer monitoring of the fetus.
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Absent End-Diastolic Velocity (AEDV): Means that blood flow stops completely during diastole. This is a more serious finding.
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Reversed End-Diastolic Velocity (REDV): Indicates that blood is flowing backwards during diastole. This is the most severe finding and requires immediate medical intervention.
Example
If a Doppler ultrasound shows a significantly reduced or absent EDV in the umbilical artery, it suggests that the placenta isn't functioning optimally. This could lead to the fetus not receiving enough oxygen and nutrients, potentially causing fetal growth restriction or other complications. In such cases, doctors would closely monitor the pregnancy, possibly recommending early delivery.
