Fetal Dopplers- A Review

Kemoria Granberry DO

Arterial◦ Umbilical◦ Middle Cerebral◦ Uterine

Venous◦ Ductus venosus

Types of Dopplers

Fetal-placental unit Progression

◦ DecreasedAbsentReversed Measurements

◦ S/D(Systolic to Diastolic) Ratio◦ PI (Pulsatility Index)

Uniformity◦ Waveforms vary along length of cord◦ Absence of fetal breathing◦ Uniform waveforms

Umbilical Artery

Why the MCA? Progression

◦ Increased EDFV◦ Decreased PI

Measurement◦ Peak Systolic Velocity◦ Pulsatility Index◦ Cerebro-placental ratio

Middle Cerebral Artery

Physiologic status of right ventricle Progression

◦ Decreased Absent Reversed flow in a wave Measurement

Uniformity?

Ductus Venosus

Progressive decrease in impedence throughout pregnancy

Abnormal trophblastic invasion Measurement

◦ Notch◦ PI

Uterine Artery

Q1: Should doppler ultrasound assessment be

performed in low risk and/or high risk

pregnancies as screening test for IUGR?

Umbilical dopplers◦ No◦ Goffinet et al

Meta analysis 1997 4 trials; n 11,275 Trials to date underpowered to determine utility of screening

Uterine dopplers◦ No◦ Chien et al

Meta analysis 28 trials ; n=3000 Abnormal result more likely to predict IUGR (liklihood ratio)

◦ Cnossen et al Meta analysis 61 trials; n= 41000 Abnormal results corelated more with high risk pregnancies, though

liklihood ratio remain high in low risk pregnancies as well

Q1

Q2: What are the benefits and limitations of

doppler studies of each vessel when

IUGR is suspected?

Umbilical Doppler◦ Significant reductions in IOL, CS, perinatal deaths◦ No validated interventions

Middle Cerebral Dopplers◦ May identify IUGR fetuses at risk for CS for NRFHT

and neonatal acidosis◦ May identify IUGR fetuses at risk for long term

neurodevelopment delay in presence of normal umbilical dopplers

◦ No validated interventions Venous Dopplers

◦ Identifies severely compromised IUGR fetus

Q2

Q3: What is the usual progression of doppler

abnormalities in fetuses with suspected IUGR? Is this

progression consistant/reliable?

Q3. Early – Brain sparing

◦ Inc impedence in UA ◦ Dec impedence in MCA◦ MCA normalization

Late – Heart Sparing◦ Inc flow through DV improve left ventricular

output◦ Increased Absent Reversed DV◦ Increased central venous pressure ◦ Umbilical venous pulsations

Validated in preterm idiopathic IUGR fetuses

Q4: What dopplers study regimen should be initiated for suspected

IUGR? What other antepartum testing may be helpful in this setting?

Q4. Initiate

◦ Viability ◦ Suspected IUGR – differentiate hypoxic growth

restricted fetus from non hypoxic small fetus Frequency

◦ Weekly, q 2-4 weeks, 3-4x’s a week◦ Determined by severity of doppler abnormality

Other testing ◦ Twice weekly NST with weekly AFI◦ Weekly BPPs

What interventions are available and should be considered based

on abnormal fetal doppler velocimetry studies?

Q5. Interventions

◦ BTMZ◦ Hospitalization◦ Timing of delivery◦ ANT