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Objective To compare the reliability of Doppler blood flow measurements of the fetal aortic isthmus (AoI) according to whether the sampling plane is obtained from the traditional longitudinal aortic arch (LAA) view or the more recently described three vessels and trachea (3VT) view of the fetal upper mediastinum. Methods Doppler blood flow measurements of pulsatility index (PI), resistance index (RI), peak systolic (PSV), end-diastolic (EDV) and time-averaged maximum (TAMXV) velocities were performed in the AoI of 40 fetuses between 24 and 36 weeks of gestation. All measurements were sampled in two different sonographic planes of the AoI: the LAA view, at a few millimeters beyond the origin of the left subclavian artery, and the 3VT view, just before the V-shaped junction of the aortic and ductal arches. All scans were performed by the same observer. The reliability of Doppler blood flow measurements was assessed by calculating intraclass correlation coefficients (ICCs) and limits of agreement between the two different sonographic sites evaluating the AoI. Results Mean values of PI, RI, PSV, EDV and TAMXV were similar in the LAA and 3VT views. The PI and vascular velocities were reliably measured from both sonographic sites. ICCs for variability of measurements were 0.78, 0.63, 0.63, 0.60 and 0.55 for PI, RI, PSV, EDV and TAMXV, respectively. Limits of agreement revealed minimal disagreement between the two sites of evaluation of the AoI for all measurements. Conclusions On the basis of our observations, Doppler blood flow measurements across the fetal AoI can be reliably obtained from both the 3VT and the traditional LAA sonographic views. Since the transverse upper thoracic 3VT plane is achievable in most fetal positions, Doppler study of the AoI appears to be easier than expected. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.

Objective To evaluate the impact of ultrasound cervical length measurement on duration of hospital stay in patients admitted for threatened preterm labor. Study design This was a prospective, comparative study in 294 patients with threatened preterm labor in three hospitalization units (Units A, B and C). In the first phase of the study (observational), cervical length was measured by transvaginal ultrasound, but managing physicians were blinded to the results. In the second phase (interventional), physicians from Unit A remained blinded to cervical length information, but Units B and C incorporated these data into their clinical management protocols. Early discharge was contemplated if the cervix measured 25 mm or more on admission (Unit B) or no changes were observed over 48 h (Unit C). Duration of hospital stay and delivery rates within 7 days and before 37 weeks' gestation were recorded. Results Hospital stay was significantly reduced in Units B and C in the interventional phase, while no changes were observed in Unit A. Delivery rates within 7 days and before 37 weeks' gestation were similar in the three units during the two stages of the study. Conclusion Routine use of ultrasound cervical length assessment in patients admitted with threatened preterm labor may reduce the duration of hospital stay without increasing the rate of preterm births. These data should be confirmed by means of an appropriately designed randomized clinical trial. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.

Objectives To assess the value of middle cerebral artery Doppler indices obtained from different sampling sites in predicting umbilical cord gases at delivery in prolonged pregnancies. Methods This was a prospective study of consecutive pregnant women referred for prolonged-pregnancy surveillance. The predictive value of distal and proximal middle cerebral artery Doppler indices for cord blood gases was evaluated in women who delivered within 48 h of their last antenatal test using stepwise multiple regression. Results There was a significant linear correlation between proximal and distal middle cerebral artery pulsatility indices (R = 0.777; P < 0.0001), the mean values being 1.49 (SD, 0.45) and 1.56 (SD, 0.47), respectively. There was also a linear correlation between proximal and distal cerebroplacental ratios (R = 0.68; P < 0.0001), the mean values being 1.85 (SD, 1.96) and 1.92 (SD, 1.89), respectively. The stepwise multiple regression analysis for umbilical artery pH showed that once the distal middle cerebral artery pulsatility index was introduced into the model, the addition of any variable did not result in a significant improvement of the predictive capacity. The model showed a coefficient of determination (R2) of 0.079. There was a significant correlation between umbilical artery pO2 and both proximal middle cerebral artery pulsatility index (positive) and the occurrence of elective Cesarean section (negative). This model accounted for 21% of the variance (R2 = 0.21). No other variables added any significant prediction for pO2. Conclusions In post-term pregnancies the proximal middle cerebral artery pulsatility index significantly predicts umbilical artery pO2 at delivery but does not predict pH. There is a weak association between distal middle cerebral artery pulsatility index and pH but, as this only explains 8% of the variance, it is of little clinical value. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.

Objective To compare Doppler evaluation of the ductus venosus and contraction stress test (CST) in the prediction of adverse perinatal outcome in growth-restricted fetuses with evidence of hemodynamic redistribution and a non-reactive non-stress test (NST). Methods Data were collected from all singleton pregnancies seen in our Fetal Surveillance Unit who underwent antenatal monitoring for fetal growth restriction, non-reactive NST and arterial redistribution beyond 26 weeks of pregnancy. Patients were divided into four groups based on their CST and ductus venosus waveform results. Perinatal outcome was evaluated by means of four variables: the need for admission to the neonatal intensive care unit (NICU), need for neonatal intubation, an umbilical artery pH < 7.10 and significant neonatal morbidity. Outcome was compared among fetuses delivered within 3 days of their antenatal test. Logistic regression analysis was used to analyze the relation between predictive and outcome variables. Results Sixty-eight women met the inclusion criteria for the study. The positive predictive value of the CST was 45% for admission to the NICU, 13% for significant neonatal morbidity, 26% for need of neonatal intubation and 29% for umbilical artery pH < 7.10. The positive predictive values of abnormal ductus venosus waveform (ADVW) were 81.5%, 26%, 48% and 55%. Groups with ADVW showed significantly poorer neonatal outcome. No significant differences were observed when CST results were compared. Logistic regression analysis showed that both gestational age at delivery and ADVW significantly predict the occurrence of adverse perinatal outcome. Conclusion In growth-restricted fetuses with hemodynamic redistribution and a non-reassuring NST, Doppler assessment of the ductus venosus correlates with adverse perinatal outcome. In this clinical situation there is no benefit of CST in terms of prediction. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.