Fetal growth restriction can result from a variety of maternal, fetal, and placental
conditions. Umbilical artery Doppler assesses the impedance to blood flow along the
fetal component of the placental unit. An abnormal umbilical artery waveform reflects
the presence of placental insufficiency and can help differentiate the growth-restricted
fetus from the constitutionally small, thus guiding further management. The presence
of persistently absent end diastolic flow and reversed end diastolic flow are an indication
for inpatient antenatal surveillance and preterm delivery. There is no consensus on
the optimal management of intermittent absent end diastolic flow due to a lack of
data to support the ideal delivery timing for growth restricted fetuses with this
To estimate the risks of adverse perinatal outcomes amongst growth restricted pregnancies
with persistently elevated, intermittently absent, and persistently absent end diastolic
flow. Fetal growth restriction is a common condition that is associated with an increased
risk of fetal morbidity and mortality. Intermittently absent umbilical artery end
diastolic flow may be identified among pregnancies with fetal growth restriction.
The fetal risks associated with persistently absent end diastolic flow have been described,
however risks associated with intermittent absent end diastolic flow are not as well
We performed a retrospective cohort study including non-anomalous, singleton, growth
restricted pregnancies that received umbilical artery Doppler assessment at our institution
from 2009-2020. Fetuses were classified into three categories: elevated umbilical
artery Doppler, intermittent absent end diastolic flow, and persistently absent end
diastolic flow. Doppler categories were classified by the most severe in the pregnancy.
The primary outcome was a composite of neonatal morbidity.
233 fetuses met criteria. 78 (33.0%) had elevated umbilical artery Doppler waveforms,
37 (16.0%) had intermittent absent end diastolic flow and 119 (51.0%) had absent end
diastolic flow. The composite outcome was statistically different between groups occurring
in 16.9% with elevated umbilical artery Doppler waveforms (13/77), 35.1% (12/39) with
intermittent absent end diastolic flow and 56.3% (65/127) with absent end diastolic
flow (p<0.001). The odds ratio for the composite outcome was significantly increased
in absent end diastolic flow (OR 6.15, 95% CI 3.14-12.80) and not significantly increased
for intermittently absent end diastolic flow (OR 2.46, 95% CI 0.98-6.19) when compared
to elevated umbilical artery Doppler waveforms. When adjusted for gestational age
at delivery and antenatal steroids, no difference was seen in the primary outcome
for intermittent absent end diastolic flow (adjusted OR 0.73, 95% CI, 0.20-2.68) and
AEDF (adjusted OR 1.44, 95% CI, 0.51-4.07).
Amongst growth restricted pregnancies, intermittent absent end diastolic flow is associated
with a similar rate of composite neonatal morbidity as persistently elevated Doppler
waveforms. Additionally, there is no difference in composite neonatal morbidity between
the three groups when corrected for gestational age at delivery and antenatal steroid
administration. These similar outcomes should be considered when creating an antenatal
surveillance plan and discussing the potential for outpatient management.