Rate of deterioration of umbilical artery Doppler indices in fetuses with severe early-onset fetal growth restriction

Abstract

ObjectiveTo examine risk factors for the development of absent or reversed end-diastolic velocity (A/REDV) and the time intervals of deterioration from normal UA EDV by S/D, PI or RI to decreased and A/REDV in fetuses with early-onset severe FGR. Study DesignRetrospective cohort study performed from 2005 to 2020. All singleton pregnancies with severe (estimated fetal weight [EFW] or abdominal circumference [AC] below the 3rd percentile) and early-onset (diagnosed between 20 0/7 to 31 6/7 weeks of gestation) were included. Fetal genetic or structural anomalies, suspected congenital infections, A/REDV at diagnosis, poor pregnancy dating and absence of follow-up ultrasounds were excluded. EFW, AC and Doppler indices were reviewed longitudinally from diagnosis to delivery. To examine risk factors for A/REDV, we performed backward stepwise logistic regression and calculated odds ratio with 95% confidence interval (CI). Kaplan-Meier curves were compared using log-rank test. ResultsA total of 985 patients met the inclusion criteria and 79 (8%) progressed to A/REDV. Factors associated with development of A/REDV included gestational age at diagnosis (AOR 4.88 [2.55 – 9.37, 95% CI] at 20 0/7 to 23 6/7 weeks and AOR 1.56 [0.86-2.82, 95%CI] at 24 0/7 to 27 6/7 weeks compared to 28 0/7 to 31 6/7 weeks) and presence of chronic hypertension (CHTN) with AOR 2.37 (1.33 – 4.23, 95% CI). Rates of progression from diagnosis of FGR with normal UA Doppler to A/REDV were significant after 4 weeks from diagnosis (5.84% [4.50 – 7.57, 95% CI]). Regarding the Doppler indices, the progression from normal values to abnormal indices was similar in 1 and 2 weeks however the progression from normal to abnormal S/D ratio compared to PI or RI were higher at 4 and 6 weeks. Deterioration from abnormal indices to A/REDV was shorter with abnormal RI and PI when compared to S/D ratio at 2, 4 and 6 weeks after diagnosis and at 6 weeks, respectively. ConclusionEarlier gestational age at diagnosis and CHTN are considered risk factors for Doppler deterioration and development of A/REDV in the UA. With normal Doppler indices, significant deterioration and progression to A/REDV is unlikely until 4 weeks after diagnosis. Abnormal S/D ratio seems to be appear first. However, abnormal PI or RI was associated with A/REDV.