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Disparate blood flow patterns in parallel umbilical arteries
M Predanic1, J Kolli, P Yousefzadeh
1Department of Obstetrics and Gynecology, The New York Flushing Hospital Medical Center, 11355, USA. amfromsa@aol.com
Obstetrics and Gynecology
|May 8, 1998
Summary
Umbilical artery blood flow resistance often differs between paired vessels in pregnancy. This difference decreases as gestation progresses, potentially aiding in the evaluation of fetal well-being.
Area of Science:
- Perinatology
- Fetal Physiology
- Vascular Ultrasound
Background:
- Umbilical arteries are crucial for nutrient and oxygen transfer to the fetus.
- Variations in umbilical artery resistance can indicate potential fetal compromise.
Purpose of the Study:
- To compare blood flow resistance between the two umbilical arteries within the same cord site during the latter half of pregnancy.
Main Methods:
- Eighty singleton pregnancies were evaluated cross-sectionally (20-40 weeks' gestation).
- Systolic-diastolic ratio (S/D) was measured for each umbilical artery.
- The higher (S/Dmax) and lower (S/Dmin) values, and their percent difference, were calculated and stratified by gestational age.
Main Results:
- Overall, S/Dmax was significantly higher than S/Dmin (P < .001).
- The mean percent difference between paired arteries decreased significantly with advancing gestation (P < .001).
- A difference >20% was observed in 29% of pairs, predominantly in earlier gestations.
Conclusions:
- Significant differences in umbilical artery blood flow resistance are common.
- This disparity diminishes with advancing pregnancy, possibly due to Hyrtl anastomosis maturation.
- Such differences may serve as an early marker for fetal hypoxia or aid in interpreting fetal status.