Volumetric flow in the umbilical artery: normative data

Area of Science:

• Obstetrics and Gynecology
• Fetal Medicine
• Cardiovascular Physiology

Background:

• Accurate assessment of fetal well-being is crucial in obstetrics.
• Umbilical artery blood flow is a key indicator of placental function and fetal development.
• Establishing normative data is essential for identifying abnormal flow patterns.

Purpose of the Study:

• To establish normative data for volumetric blood flow in the umbilical artery.
• To present flow rates in cc/min and cc/min/kg throughout gestation (18-40 weeks).
• To correlate blood flow with fetal biometry and velocimetric indices.

Main Methods:

• Utilized pulsed Doppler and color flow Doppler to measure umbilical artery flow in 252 normal pregnancies.
• Measurements were taken between 18-40 weeks gestation with an angle of insonation of 30-60 degrees.
• Simultaneous velocimetry studies, fetal biometry, and anatomic surveys were performed.

Main Results:

• Demonstrated a consistent increase in umbilical artery volumetric blood flow (cc/min) as pregnancy progressed.
• Observed a steady decline in flow per kilogram (cc/min/kg) with increasing fetal weight.
• Umbilical artery diameter showed an increase, plateauing around 32-34 weeks gestation.

Conclusions:

• Volumetric blood flow in the umbilical artery can be reliably measured using Doppler ultrasound.
• Normative data for umbilical artery blood flow from 18-40 weeks gestation are presented.
• This data provides a valuable reference for assessing fetal health and placental function.