SMFM clinical guidelineDoppler assessment of the fetus with intrauterine growth restriction
Section snippets
Umbilical artery Doppler
Doppler velocimetry of the umbilical artery assesses the resistance to blood perfusion of the fetoplacental unit (Figure 1, A). As early as 14 weeks, low impedance in the umbilical artery permits continuous forward flow throughout the cardiac cycle.7 Maternal or placental conditions that obliterate small muscular arteries in the placental tertiary stem villi result in a progressive decrease in end-diastolic flow in the umbilical artery Doppler waveform until absent (Figure 1, B) and then
Middle cerebral artery Doppler
Under normal conditions, the cerebral circulation is a high impedance circulation with continuous forward flow present throughout the cardiac cycle14 (Figure 2, A). The middle cerebral arteries, which carry >80% of the cerebral circulation, represent major branches of the circle of Willis and are the most accessible cerebral vessels for ultrasound imaging in the fetus.15 The middle cerebral artery can be imaged with color Doppler ultrasound in a transverse plane of the fetal head obtained at
Ductus venosus Doppler
Doppler waveforms obtained from the central venous circulation in the fetus reflect the physiologic status of the right ventricle. Doppler waveforms are obtained from the ductus venosus in a transverse or sagittal view of the fetal abdomen at the level of the diaphragm.22 By superimposing color Doppler on the gray-scale image, the ductus venosus can be identified as it branches from the umbilical vein (Table). Variable high flow velocities, reflected as a mixture of colors on color Doppler
Uterine artery Doppler
Doppler velocimetry of the uterine arteries reveals a progressive decrease in impedance with advancing gestational age.25, 26 This decrease in impedance is thought to reflect a maternal adaptation to pregnancy resulting from trophoblastic invasion of the maternal spiral arterioles in the first half of gestation.27 The uterine artery can be demonstrated by color Doppler velocimetry as it originates from the anterior division of the hypogastric artery, and just before it enters the uterus at the
Question 1. Should Doppler ultrasound assessment be performed in low-risk and/or high-risk women as a screening test for IUGR? (Levels II and III)
Routine umbilical artery Doppler screening for the subsequent development of IUGR in a low-risk population has not been shown to be effective in predicting IUGR. A metaanalysis of 4 trials (n = 11,375), which included 2 studies of low-risk populations and 2 studies of unselected populations, found no significant difference in antenatal hospitalization, obstetric outcomes, or perinatal morbidities with systematic use of umbilical artery Doppler as compared with control groups.32 The metaanalysis
Question 2. What are the benefits and limitations of Doppler studies of each vessel when IUGR is suspected? (Levels I, II, and III)
Clinicians have the options of interrogating several vessels, with umbilical artery, middle cerebral artery, and ductus venosus being the ones most studied.
Umbilical artery Doppler evaluation of pregnancies with suspected IUGR has been shown to significantly reduce inductions of labor (relative risk [RR], 0.89; 95% CI, 0.80–0.99), cesarean deliveries (RR, 0.90; 95% CI, 0.84–0.97), and perinatal deaths (RR, 0.71; 95% CI, 0.52–0.98; 1.2% vs 1.7%; number needed to treat = 203; 95% CI, 103–4352)
Question 3. What is the usual progression of Doppler abnormalities in suspected IUGR? Is this progression consistent/reliable? (Levels II and III)
In the presence of hypoxemia, adaptive changes in the fetal circulation can be detected by Doppler ultrasound examination. These changes manifest themselves in a variable fashion in different fetuses, but some general patterns of progression can be recognized. Early adaptation includes preferential shunting and distribution of blood flow to the fetal brain, heart, and adrenal glands at the expense of the splanchnic and peripheral circulation. This adaptive mechanism, termed “brain sparing,” is
Question 4. What Doppler study regimen should be initiated for suspected IUGR? What other antepartum testing may be helpful in this setting? (Levels I, II, and III)
Umbilical artery Doppler evaluation of the fetus with suspected IUGR can help differentiate the hypoxic growth-restricted fetus from the nonhypoxic small fetus, and thereby reduce perinatal mortality, and unnecessary interventions.2, 8, 35, 49, 50, 51, 52 Umbilical artery Doppler studies to assess for the presence of increased placental impedance and fetal cardiovascular adaptation to hypoxemia should be initiated when IUGR is suspected and the fetus is considered potentially viable. Umbilical
Question 5. What interventions are available and should be considered based on abnormal fetal Doppler velocimetry studies? (Levels II and III)
Umbilical artery Doppler blood flow studies can be used clinically to guide interventions such as the frequency and type of other fetal testing, hospitalization, antenatal corticosteroid administration, and delivery (Figure 5). Sometimes these Doppler studies can also help defer intervention. For example, in cases with suspected IUGR and absent or reversed end-diastolic flow <25 weeks, aggressive obstetrical interventions may be deferred until a later gestational age given the poor prognosis
Levels II and III evidence, level C recommendation
- 1
Doppler of any vessel is not recommended as a screening tool for identifying pregnancies that will subsequently be complicated by IUGR.
Levels I evidence, level A recommendation
- 2
Antepartum surveillance of a viable fetus with suspected IUGR should include Doppler of the umbilical artery, as its use is associated with a significant decrease in perinatal mortality.
Levels II and III evidence, level C recommendation
- 3
Once IUGR is suspected, umbilical artery Doppler studies should be performed usually every 1-2 weeks to assess for deterioration; if normal, they can be extended to less
References (64)
- et al.
A practical classification of newborn infants by weight and gestational age
J Pediatr
(1967) Arterial and venous Doppler in the diagnosis and management of early onset fetal growth restriction
Early Hum Dev
(2005)- et al.
Adverse pregnancy outcome and association with small for gestational age birthweight by customized and population-based percentiles
Am J Obstet Gynecol
(2009) - et al.
Absent end-diastolic flow in first trimester umbilical artery
Lancet
(1988) - et al.
Umbilical artery flow velocity waveforms and placental resistance: the effect of embolizations of the umbilical circulation
Am J Obstet Gynecol
(1987) - et al.
Effect of placental embolization on the umbilical artery velocity waveform in fetal sheep
Am J Obstet Gynecol
(1989) - et al.
Middle cerebral artery flow velocity waveforms in normal and small-for-gestational age fetuses
Am J Obstet Gynecol
(1992) - et al.
Longitudinal quantitation of middle cerebral artery blood flow in normal human fetuses
Am J Obstet Gynecol
(1993) - et al.
Distribution of the circulation in the normal and asphyxiated fetal primate
Am J Obstet Gynecol
(1970) - et al.
The Doppler cerebroplacental ratio and perinatal outcome in intrauterine growth restriction
Am J Obstet Gynecol
(1999)
Fetal growth restriction due to placental disease
Semin Perinatol
Doppler ultrasonographic features of the developing placental circulation; correlation with anatomic findings
Am J Obstet Gynecol
The role of uterine artery Doppler in predicting adverse pregnancy outcome
Best Pract Res Clin Obstet Gynecol
New Doppler technique for assessing uteroplacental blood flow
Lancet
Society for Maternal-Fetal Medicine: uterine artery Doppler flow studies in obstetric practice
Am J Obstet Gynecol
Venous Doppler in the prediction of acid-base status of growth-restricted fetuses with elevated placental blood flow resistance
Am J Obstet Gynecol
Integrated testing and management in fetal growth restriction
Semin Perinatol
Umbilical artery Doppler screening for detection of the small fetus in need of antepartum surveillance
Am J Obstet Gynecol
A pilot randomized controlled trial of two regimens of fetal surveillance for small-for-gestational-age fetuses with normal results of umbilical artery Doppler velocimetry
Am J Obstet Gynecol
Fetal assessment based on fetal biophysical profile scoring, VIII: the incidence of cerebral palsy in tested and untested perinates
Am J Obstet Gynecol
Comparison of the modified biophysical profile to a “new” biophysical profile incorporating the middle cerebral artery to umbilical artery velocity flow systolic/diastolic ratio
Am J Obstet Gynecol
Potential risks and benefits of antenatal corticosteroid therapy prior to preterm birth in pregnancies complicated by severe fetal growth restriction
Obstet Gynecol Clin North Am
Intrauterine growth restriction; ACOG practice bulletin no. 12
Relationship between arterial and venous Doppler and perinatal outcome in fetal growth restriction
Ultrasound Obstet Gynecol
Relationship between monitoring parameters and perinatal outcome in severe, early intrauterine growth restriction
Ultrasound Obstet Gynecol
Pathology and clinical implications of abnormal umbilical artery Doppler waveforms
Ultrasound Obstet Gynecol
Birth weight in relation to morbidity and mortality among newborn infants
N Engl J Med
Doppler ultrasound in obstetrics and gynecology
Doppler ultrasonography and fetal well being
Middle cerebral artery peak systolic velocity: technique and variability
J Ultrasound Med
Middle cerebral artery peak systolic velocity: a new Doppler parameter in the assessment of growth-restricted fetuses
Ultrasound Obstet Gynecol
Reference resistance indices of the umbilical, fetal middle cerebral and uterine arteries at 24-42 weeks of gestation
Ultrasound Obstet Gynecol
Cited by (0)
The authors report no conflict of interest.
Reprints not available from the authors.