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Extent of absent end‐diastolic flow in umbilical artery and outcome of pregnancy
Author(s) -
Kinoshita M.,
Thuring A.,
Morsing E.,
Maršál K.
Publication year - 2021
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.23541
Subject(s) - medicine , umbilical artery , gestational age , birth weight , obstetrics , pregnancy , velocimetry , intrauterine growth restriction , retrospective cohort study , uterine artery , diastole , fetus , gestation , blood pressure , genetics , physics , optics , biology
Objective To investigate if the extent of absent end‐diastolic flow (AEDF) on umbilical artery (UA) Doppler velocimetry predicts pregnancy outcome. Methods This was a retrospective observational study based on data from 25 000 Doppler examinations of UA flow performed between 1998 and 2017 at the Blood Flow Laboratory, Level III Perinatal Center, Lund, Sweden. 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 (T a /T tot 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 T a /T tot ratio for intrauterine death and any (intrauterine or postnatal) death was assessed. Results 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 (range, 163–279 days) (i.e. 27 + 0 weeks (range, 23 + 2 to 39 + 6 weeks)), birth weight was 650 g (range, 320–3326 g) and deviation from expected birth weight (standard deviation score) was –2.975 (range, –6.38 to 0.69). There were 15 (9%) intrauterine and 26 (15%) postnatal deaths. The principal outcome variables and their relationship with Doppler velocimetry results did not differ significantly between singletons and twins, giving a rationale for using the T a /T tot ratio in the total study group. Mean T a /T tot ratio was 0.42 ± 0.08 and 0.34 ± 0.08 in stillborn and liveborn fetuses, respectively ( P = 0.002). For fetuses examined before 30 weeks' gestation, a T a /T tot 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 a NPV of 85% (AUC, 0.66). Conclusions In fetuses with AEDF in the UA, 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. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.