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375: Ductus venosus flow velocity waveforms indices and arterial cord pH in IUGR fetuses delivered at 32 weeks

      Objective

      In IUGR fetuses, an abnormal ductus venosus (DV) Doppler is considered an ominous sign because it is thought to be related to irreversible decompensation and acidemia. Several indices have been described to quantify DV Doppler waveforms: a) pulsatility index (PI); b) a-wave reversed flow (RF); and, c) SIA index [peak systolic velocity/(isovolumetric relaxation + a-wave)]. The aim of this study was to determine which index is more highly correlated with acidemia at birth.

      Study Design

      Thirty-five IUGR fetuses (EFW<10th percentile and abnormal umbilical artery PI) were delivered between 23.1 and 32 weeks' gestation (median: 27.3 weeks). An abnormal DV Doppler was not considered an indication for delivery. The PI, the RF, and the SIA indices were correlated with the perinatal death and the arterial cord pH determined at birth, which was considered abnormal if the value was <7.10 and/or if the base deficit was <-9.0 (2 SD below the mean for preterm neonates). We also determined the sensitivity and specificity for each index for perinatal death or acidemia.

      Results

      All fetuses were delivered by cesarean section. Indications for delivery were non-reassuring fetal testing or maternal indications in 26 cases and lack of interval growth in 2 fetuses. There were 7 IUFDs. Birth weights ranged from 282 to 1245 grams (median: 530 grams). One fetus had an abnormal pH and 10 also had an abnormal base deficit. The RF had the best sensitivity (73%, CI: 55-95% vs. 61%, CI: 47-81%) and the SIA index had the best specificity (95%, CI: 77-99% vs. 78%, CI: 58-90%). The PI had the worst sensitivity and specificity of the three indices.

      Conclusion

      Our data suggest that DV RF has the best sensitivity for perinatal death or acidemia, while the SIA index has the best specificity. Both the RF and the SIA index should be considered as part of the standard evaluation of IUGR fetuses.