Extent of absent end-diastolic flow in umbilical artery and
To investigate if the extent of absent end-diastolic flow (AEDF) on the umbilical artery (UA) Doppler velocimetry predicts pregnancy outcome study was conducted. This was a retrospective observational study based on data from 25?000 Doppler examinations of UA flow. All pregnancies with AEDF in the UA were identified, and the duration of AEDF as a proportion of the total duration of the cardiac cycle (Ta/Ttot ratio) was measured in digital images of the Doppler spectrum recorded at the last examination showing AEDF before delivery. Clinical data on pregnancies and neonatal outcomes were extracted from the regional perinatal database and the hospital patient records. The predictive performance of the Ta/Ttot ratio for intrauterine death and any (intrauterine or postnatal) death was assessed.

A total of 170 fetuses (122 (72%) singletons and 48 (28%) twins) were included in the study. Median gestational age at birth was 189.5?days, birth weight was 650?g, and deviation from expected birth weight (standard deviation score) was –2.975. There were 15 (9%) intrauterine and 26 (15%) postnatal deaths. For fetuses examined before 30?weeks gestation, a Ta/Ttot ratio cut-off of 0.30 predicted intrauterine death with 92% sensitivity and a negative predictive value (NPV) of 98% (area under receiver-operating-characteristics curve (AUC), 0.74) and predicted any death with 83% sensitivity and an NPV of 85% (AUC, 0.66).

In fetuses with AEDF in the UA, the duration of absent flow for at least 30% of the total cardiac cycle length might predict the risk of fetal demise, even when assessed before 30?weeks gestation. This finding is particularly relevant to growth-restricted fetuses. After evaluation in further studies, the extent of AEDF might facilitate obstetric decision-making in very preterm growth-restricted fetuses.