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Clinical Significance of Intermittent Absent End Diastolic Flow of the Umbilical Artery in Fetal Growth Restriction

Published:November 08, 2022DOI:https://doi.org/10.1016/j.ajogmf.2022.100800

      AJOG at a Glance

      • A
        We conducted this study to estimate the risks of adverse perinatal outcomes amongst growth restricted pregnancies with persistently elevated, intermittently absent, and persistently absent end diastolic flow of the umbilical artery.
      • B
        Intermittent absent end diastolic flow is associated with a similar rate of composite neonatal morbidity as a persistently elevated Doppler waveform. Additionally, there is no difference in composite neonatal morbidity between the three groups when corrected for gestational age at delivery and antenatal steroid administration.
      • C
        This study compares clinical outcomes of fetal growth restriction with intermittent absent end diastolic flow of the umbilical artery against outcomes of those with elevated umbilical artery pulsality index and absent end diastolic flow.

      Abstract

      Background

      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 finding.

      Objectives

      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 known.

      Study design

      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.

      Results

      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).

      Conclusions

      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.

      Key words

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