Placental integrity, specifically vascular resistance, may be assessed by evaluating flow in the umbilical arteries using Doppler ultrasound. When this is done with high risk pregnancies the perinatal death rate is reduced and interventions may be appropriately timed or withheld. “High risk” in these investigations were principally intrauterine growth restriction and maternal hypertension. When Doppler studies were extended to low-risk pregnancies however there was no improvement in outcome and abnormal results were more likely to be false positives.
Sources:
Alfirevic Z, et al. Fetal and umbilical Doppler ultrasound in high-risk pregnancies. Cochrane Database Syst Rev. 2013 Nov 12;(11):CD007529. PMID: 24222334.
Alfirevic Z, et al. Fetal and umbilical Doppler ultrasound in normal pregnancy. Cochrane Database Syst Rev. 2015 Apr 15;(4):CD001450. PMID: 25874722.