Predictiveness of antenatal umbilical artery Doppler for adverse pregnancy outcome in small-for-gestational-age babies according to customised birthweight centiles: population-based study

Objective  To examine the relationship between smallness at birth and the predictive value of umbilical artery Doppler.
Design  Retrospective cohort.
Setting  Tertiary referral university hospital, Barcelona.
Population  A total of 7645 singleton pregnancies delivered between January 2002 and June 2004.
Methods  The associations with adverse outcome were assessed for small-for-gestational-age (SGA) babies according to customised standards who had normal and abnormal umbilical artery Doppler.
Main outcome measures  Neonatal morbidity and perinatal mortality.
Results  Of the 369 SGA fetuses that had been identified antenatally, 70 (19%) had an abnormal umbilical artery Doppler and the babies from these pregnancies had a higher risk for neonatal morbidity when compared with babies with normal birthweight (OR 3.99, 95% CI 1.04–11.03). However, the remaining 299 (81%) fetuses with normal umbilical artery Doppler also had an elevated risk of neonatal morbidity (OR 2.26, 95% CI 1.04–4.39). Overall, many of the instances of adverse outcome associated with smallness for gestational age were attributable to the group with normal Doppler than to the group with abnormal Doppler.
Conclusion  Normal antenatal umbilical artery Doppler cannot be taken as an indicator of low risk in pregnancies where the fetus is SGA according to customised percentiles.     

Middle cerebral artery to umbilical artery resistance index ratio in the prediction of neonatal outcome.

OBJECTIVE: The objectives of this study were to evaluate the usefulness of the middle cerebral artery to umbilical artery resistance index ratio (C/U ratio) as a predictor of adverse perinatal outcome, and to show that the absence of fetal umbilical artery end-diastolic velocity (AEDV) in SGA fetuses is associated with high morbidity and mortality. METHOD: In this prospective study, color Doppler flow imaging was used for the estimation of the C/U ratio in fetuses that were small for their gestational age, in 70 singleton pregnancies between 29 and 42 weeks of gestation. The subjects were categorized into two groups, with Group A consisting of 35 small for gestational age (SGA) fetuses with a normal C/U ratio (1.05 or higher), and Group B comprising 35 SGA fetuses with an abnormal C/U ratio (below 1.05). RESULT: The mean C/U ratio values for birth weight and gestational age were higher in group A than in group B. Fetuses born to mothers in group B stayed longer in the neonatal special care unit (NSCU), whereas the period from ultrasound examination to delivery was higher in the cases in group A. A higher percentage of mothers with an abnormal C/U ratio underwent cesarean section. Fetuses with an absent end-diastolic velocity of the umbilical artery had a higher morbidity. Three stillbirths occurred in fetuses with an absent end-diastolic velocity of the umbilical artery. CONCLUSION: Our results suggest that the C/U ratio is a good predictor of neonatal outcome, and could be used to identify fetuses at risk of morbidity and mortality. Fetal umbilical artery AEDV with intrauterine growth restriction is associated with high perinatal morbidity and mortality.     

Fetal blood flow in pregnancies complicated by intrauterine growth retardation

A noninvasive pulsed Doppler ultrasound technique was used to characterize blood flow in the descending thoracic aorta and the intra-abdominal part of the umbilical vein in 159 fetuses suspected of intrauterine growth retardation (IUGR) on the basis of ultrasound fetometry. From this group, 74 infants with IUGR (defined as gestational age-related birth weight of 2 standard deviations [SD] or more below the population mean) were born. The blood flow results were not available to the clinicians managing the pregnancies. Blood flow mean velocity in the fetal aorta was lower, pulsatility index and rising slope higher, and umbilical volume flow and umbilical flow per 100 g placental tissue were lower in the pregnancies with IUGR than in 21 normal pregnancies. The waveform of the maximum aortic velocity envelope was related to operative delivery for fetal distress, Apgar score, and umbilical cord blood pH. The pulsatility index and the configurational assessment of the diastolic part of the waveform were combined to form a new concept, the blood flow class. The blood flow class was abnormal in 57% of the fetuses classified as having IUGR at birth and in 93% of those growth-retarded fetuses who subsequently developed signs of fetal distress requiring operative delivery. Waveform analysis, in terms of blood flow class, seems to be a useful tool in the surveillance of fetuses when IUGR is suspected. Abnormal blood flow class is a marker of fetal distress and probably gives an earlier indication than antenatal nonstressed cardiotocography. The results of this study point to a strong association between IUGR and impaired fetal blood flow. The aortic volume blood flow, unlike waveform analysis, does not seem to be a variable sensitive enough to predict fetal outcome in the individual pregnancy.     

Intrauterine Wachstumsrestriktion

The term “intrauterine growth restriction” (IUGR) defines fetuses who fail to realize their genetically endowed growth potential. Small for gestational age (SGA) fetuses (abdominal circumference or estimated fetal weight below the 10th percentile) have to be distinguished from IUGR fetuses (SGA fetuses having abnormal umbilical artery Doppler). About 50% of SGA fetuses also have IUGR. The birth weight of 25% of IUGR fetuses is above the 10th percentile. Fetal growth is regulated by genetic and environmental factors of parental, fetal, and placental origin. In more than 50% of cases, IUGR is associated with risk factors (medical history, clinical findings). The diagnosis relies on fetal biometry; however, the sensitivity in low-risk groups is only 30–40%. Diagnostic procedures should always include Doppler sonography of the fetomaternal circulation, detailed assessment of the fetal organs by ultrasound, and, optionally, serological examinations to exclude infections and determine the karyotype.     

Neonatal nucleated red blood cell counts in small-for-gestational-age fetuses: relationship to fetoplacental Doppler studies

OBJECTIVE: To study the influence of pathologic umbilical and middle cerebral artery and uterine artery Doppler studies on the nucleated red blood cell count in small-for-gestational-age (SGA) fetuses. MATERIALS AND METHODS: Cord blood was prospectively collected during a 18-month period. 80 SGA fetuses (fetal abdominal circumference < 5th percentile) with Doppler ultrasound of the umbilical, the middle cerebral artery and both uterine arteries were enrolled in the study. SGA fetuses with normal Doppler flow velocity waveforms were allocated to group 1 (n = 23). Group 2 (n = 13) were fetuses with abnormal umbilical Doppler studies and group 3 (n = 44) were fetuses with both, pathologic umbilical and uterine artery Doppler studies. 2 fetuses in group 3 showed evidence of brain sparing, 3 fetuses presented absent-end-diastolic flow in the umbilical artery. Outcome measures included nucleated red blood cell count, Apgar scores, arterial pH and arterial base excess, venous pH, birth weight, gestational age at delivery, mode of delivery, rate of neonatal intensive care unit admission and length of stay in the neonatal intensive care unit. RESULTS: Highest nucleated red blood cell counts with lowest birth weight and gestational age were found in group 3. Decelerations of the fetal heart rate were more frequent in study group 3 and caesarean section for fetal indication was performed more often in this group. Those fetuses had to be transfered more often to the neonatal intensive care unit than fetuses of the other study groups. There was a tendency in group 3 towards lower arterial pH values and arterial base excess values. Fetuses with absent-end-diastolic flow in the umbilical artery presented highest nucleated red blood cell counts. CONCLUSION: In SGA fetuses increasing Doppler pathology seems to be correlated with increasing nucleated red blood cell count post-partum. Pathologic uterine artery flow results might have an additional impact on the number of nucleated red blood cells at birth.     

Betamethasone effects on umbilical arteries and ductus venosus Doppler velocity waveforms in growth-restricted fetuses

We studied intrauterine-growth-restricted (IUGR) fetuses with absent or reversed umbilical artery end-diastolic flow (EDF) velocity in order to evaluate the benefit of antenatal steroid therapy. Perinatal outcomes after betamethasone were evaluated where end diastolic flow returned (group I), compared with data from fetuses with persistent absent-reverse end diastolic(ARED) flow (group II). Objectives/methods: We recruited sixty-four IUGR fetuses, 28–32 weeks’ gestation, whose umbilical artery spectral tracings showed ARED flow and positive a-wave in the ductus venosus at admission. Results: Group I, 21 cases of restored EDF after betamethasone: Significant, persistent return of umbilical artery EDF flow and persistent ductus venosus a-wave were documented. Group II, 43 cases of persistent ARED flow: Persistent ARED flow in umbilical arteries and deterioration of ductus venosus waveform with significant, increasing pulsatility index and/or a-wave disappearance were documented. In group I, cardiotocographic alterations were delayed contrasted with group II, (p?=?0.03). Neonatal complications in group II were eight cases of intraventricular hemorrhage; two cases of retinopathy of prematurity; three neonatal deaths, one fetal demise; and a higher incidence of neonatal respiratory distress syndrome. Conclusions: Betamethasone treatment may have beneficial effects on restoring end-diastolic umbilical artery velocimetry and precordial waveforms. These spectral Doppler changes are related to delayed cardiotocographic alterations and to better perinatal outcomes.     

Venous Doppler in the prediction of acid-base status of growth-restricted fetuses with elevated placental blood flow resistance

OBJECTIVE: This study was undertaken to test which venous Doppler parameter offers the best prediction of acid-base status at birth in pregnancies complicated by intrauterine growth restriction (IUGR) caused by placental dysfunction. STUDY DESIGN: A prospective cross-sectional Doppler study of IUGR fetuses with abnormal umbilical artery Doppler and birth weight less than the 10th percentile. Absence of atrial systolic forward velocities in the ductus venosus (DV) (DV-RAV) and umbilical vein (UV) pulsations were noted and multiple venous indices were calculated for the inferior vena cava (IVC) and DV (IVC and DV preload index, peak velocity index [PVIV] and pulsatility index [PIV] and the DV S/a ratio). Doppler indices, UV pulsations, and DV- RAV were related to an umbilical artery cord pH <7.20, and a pH <7.00 and/or base deficit greater than -13 (severe metabolic compromise) in neonates delivered by cesarean section without labor. RESULTS: In 122 fetuses all venous Doppler indices were equally predictive of a pH <7.20, with the exception of the IVC PVIV. No Doppler index predicted severe metabolic compromise. Bayesian analysis of individual Doppler parameters showed comparable outcome prediction with the highest sensitivity for the IVC PIV (76%) and the highest specificity for DV-RAV (96%). Combined assessment of the IVC, DV, and UV provided the most accurate outcome prediction. Doppler abnormality in either vessel identified 89% of neonates with pH <7.20 (negative predictive value 92%) and 10 of 11 neonates with severe metabolic compromise. Prediction was most specific (84%) when Doppler parameters were abnormal in all 3 vessels. CONCLUSION: IVC, DV, and UV Doppler parameters correctly predict acid-base status in a significant proportion of IUGR neonates. Combination, rather than single vessel assessment provides the best predictive accuracy. While the choice of Doppler index can be guided by operator preference, familiarity with the examination technique of all 3 vessels is encouraged to offer the highest flexibility in clinical practice.     

用脐动脉血流速度比值预测高危妊娠及胎儿预后的价值

对孕３０～４２周的单胎孕妇进行了５１０人次脐动脉血流速度比值（Ｓ／Ｄ）的测定。结果表明，Ｓ／Ｄ值≥３组较Ｓ／Ｄ值＜３组的早产率，小于胎龄儿（ＳＧＡ）发生率，新生几特殊监护（ＮＩＣＵ），围产儿死亡率，妊娠高血压综合征（ＰＩＨ）及胎儿宫内生长迟缓（ＩＵＧＲ）发生率均明显增高，（Ｐ＜０．０００１）。提示Ｓ／Ｄ值对预测高危妊娠及胎儿预后有较高的临床价值。     

Doppler umbilical velocimetry in the prediction of adverse outcome in pregnancies at risk for intrauterine growth retardation

Perinatal indicators of fetal compromise were assessed according to the results of continuous-wave Doppler umbilical velocimetry for 172 patients at risk for intrauterine growth retardation (IUGR). Forty-three (25%) of the patients delivered an infant with a birth weight below the tenth percentile for gestational age. The last Doppler study before delivery was abnormal in 48.8% of the growth-retarded infants but in only 13.2% of the infants without evidence of IUGR. Furthermore, in the growth-retarded group, early delivery, reduced birth weight, decreased amniotic fluid at birth, admission to the neonatal intensive care unit, neonatal complications associated with IUGR, and a prolonged hospital stay were observed more frequently in those who had an abnormal ratio than in those with a normal ratio. The sensitivity of the systolic/diastolic ratio for an adverse perinatal outcome (operative delivery for fetal distress, neonatal morbidity associated with IUGR, and/or perinatal death) was significantly better for the infants with IUGR (66.7%) than for the infants without IUGR (27.8%; P less than .05). The predictive value of an abnormal ratio was also higher for the pregnancies complicated with IUGR (57.1%) than for those without IUGR (29.4%), but not to a statistically significant degree. These data suggest that Doppler umbilical velocimetry studies are valuable in identifying those growth-retarded fetuses at increased risk for an adverse perinatal outcome.     

Validity of umbilical artery Doppler waveform versus umbilical vein Doppler waveform in the prediction of neonatal outcome in intrauterine growth restriction cases

ObjectiveTo assess the neonatal outcome in relation to umbilical vein Doppler compared to umbilical artery Doppler in growth restricted fetuses.MethodsA total of 72 pregnant women with singleton pregnancy between 28 and 38 weeks of gestation with risk of developing intrauterine growth restriction (IUGR) were recruited to the study. All women were subjected to full assessment via detailed history, clinical examination, obstetric assessment, routine laboratory assessment and ultrasonography examination for fetal assessment. Doppler examination of umbilical artery (UA) and umbilical vein (UV) was performed. Absent or reversed UA end diastolic flow (EDF) and pulsatile flow in the umbilical vein were examined for their efficacy to predict critical outcomes (still birth, neonatal death, IUGR).ResultsA total of 13 deaths (18%) were reported; 13.9% were neonatal deaths and 4.2% were stillbirths. Fetuses were grouped according to Doppler parameters: those with normal Doppler finding (n = 35), those with resistance index (RI) (n = 20), those with Absent UA EDF (n = 10) and those with reversed UA EDF (n = 7). Pulsatile UV waveform was reported among 9.7% of patients all of them had reversed UA EDF. Patients with absent/reversed EDF have significant association with critical neonatal outcomes as lower birth weight, perinatal deaths, and lower Apgar score. UV Doppler was abnormal in patients with more severe deterioration (patients with reversed UA EDF) while it was normal in all patients with increased RI and absent UA EDF. All cases with Pulsatile UV Doppler have shown higher incidence of critical neonatal outcomes.ConclusionUV Doppler assessment can aid in detection and prediction of critical perinatal outcomes however, it required further evaluation and assessment.     

Possible role of asymmetric dimethylarginine (ADMA) in prediction of perinatal outcome in preeclampsia and fetal growth retardation related to preeclampsia

Objective: The objective of this study is to investigate maternal serum and neonatal umbilical cord asymmetric dimethylarginine (ADMA) levels in prediction of perinatal prognosis in pregnancies with preeclampsia (PE) and fetal intrauterine growth retardation (IUGR) accompanying PE (PE?+?IUGR).

Methods: Maternal serum ADMA (msADMA) and neonatal umbilical cord ADMA (ucADMA) levels were studied from 34 patients with PE, 25 patients with PE?+?IUGR, and 30 healthy pregnant controls in this prospective case–control study. Umbilical artery Doppler indices of fetuses, birth weights, Apgar scores, umbilical artery pH measurements of neonates, and admissions to neonatal intensive care unit (NICU) were recorded.

Results: Median msADMA was significantly higher in PE and PE?+?IUGR groups (p?=?0.024 and p?=?0.011, respectively), and ucADMA was significantly higher in PE and PE?+?IUGR groups than the control group (p?=?0.029 and p?=?0.018, respectively). Median msADMA and ucADMA levels were significantly higher in the PE?+?IUGR group than the PE group (p?=?0.019 and 0.021, respectively). ucADMA levels did not correlate with fetal umbilical arterial blood flow neither in the PE nor in the PE?+?IUGR group (p?=?0.518 and p?=?0.892, respectively). None was related with neonatal umbilical artery pH or NICU admission rates.

Conclusions: msADMA and ucADMA correlated with severity of PE. msADMA and ucADMA failed to predict perinatal outcome in patients with PE and PE?+?IUGR.     

Intrauterine growth restriction and absent or reverse end-diastolic blood flow in umbilical artery (Doppler class II or III): A retrospective study of short- and long-term fetal morbidity and mortality

OBJECTIVE: Absent or reverse end-diastolic flow (Doppler II/III) in umbilical artery is correlated with poor perinatal outcome, particularly in intrauterine growth restricted (IUGR) fetuses. The optimal timing of delivery is still controversial. We studied the short- and long-term morbidity and mortality among these children associated with our defined management. STUDY DESIGN: Sixty-nine IUGR fetuses with umbilical Doppler II/III were divided into three groups; Group 1, severe early IUGR, no therapeutic intervention (n = 7); Group 2, fetuses with pathological biophysical profile, immediate delivery (n = 35); Group 3, fetuses for which expectant management had been decided (n = 27). RESULTS: In Group 1, stillbirth was observed after a mean delay of 6.3 days. Group 2 delivered at an average of 31.6 weeks and two died in the neonatal period (6%). In Group 3 after a mean delay of 8 days, average gestational age at delivery was 31.7 weeks; two intra uterine and four perinatal deaths were observed (22%). Long-term follow-up revealed no sequelae in 25/31 (81%) and 15/18 (83%), and major handicap occurred in 1 (3%) and 2 patients (11%), respectively, for Groups 2 and 3. CONCLUSION: Fetal mortality was observed in 22% of this high risk group. After a mean period of follow-up of 5 years, 82% of infants showed no sequelae. According to our management, IUGR associated with umbilical Doppler II or III does not show any benefit from an expectant management in term of long-term morbidity.     

Fetal volume blood flow and umbilical artery flow velocity waveform analysis: a comparison

The estimation of fetal umbilical vein and aortic volume blood flow was compared with umbilical artery flow velocity-time waveform analysis in 42 pregnancies. The volume blood flow measurements were made with a combined linear array B-mode and pulsed Doppler ultrasound system. The umbilical artery flow velocity-time waveform analysis was made with either pulsed or continuous wave 2 MHz Doppler ultrasound and the systolic/diastolic (A/B) ratio was used as an index of flow resistance. There was no difference when continuous wave was compared to pulsed Doppler ultrasound as a method of recording flow velocity waveforms. Analysis of the umbilical artery flow velocity-time waveform was more sensitive (100%-50%) than the measurement of umbilical vein volume blood flow (ml/kg/min) in the detection of the small-for-gestational age (SGA) fetus. The predictive value of a positive test was higher (71%-45%) while specificity was similar (88%-81%). Descending aortic volume flow was reduced in only one SGA fetus. The increase in umbilical placental downstream resistance (high systolic/diastolic ratio) was associated with a reduction in the percentage of fetal aortic blood flow directed to the umbilical placental circulation.     

Umbilical and middle cerebral artery Doppler indices in patients with preeclampsia

OBJECTIVE: To compare changes in Doppler ultrasound studies of fetal circulation in normal pregnancies with those of a group of preeclamptic patients both with and without intrauterine growth retardation and to demonstrate the best index for predicting adverse perinatal outcome or IUGR. STUDY DESIGN: A cross-sectional study was performed on 125 normal pregnancies and 62 preeclamptic patients at 31-40 weeks of gestation. The umbilical artery systolic-diastolic ratio (UA S/D), UA pulsatility index (PI), the middle cerebral artery (MCA) PI, and the ratio of MCA PI to UA PI were measured. The mean values of the Doppler indices were compared. Different cut-off values (mean +/-2 S.D.) were used for the 31st-35th and the 36th-40th weeks. RESULTS: Significant differences were found between normal pregnancies and preeclamptic patients without IUGR using the mean MCA PI and the MCA PI/UA PI ratio. In the preeclamptic patients with IUGR, all the mean Doppler indices were different from those of the normal pregnancies. In the preeclamptic patients with IUGR the values were different from the preeclamptic patients without IUGR, except for the MCA PI at 31-35 weeks. The UA S/D had the highest sensitivity (88%) and diagnostic accuracy (94%) in predicting the adverse perinatal outcome. The MCA PI/UA PI ratio showed the highest predictive value in determining IUGR by a sensitivity of 84% and a diagnostic accuracy of 87%. CONCLUSION: Both abnormal umbilical Doppler indices and cerebral-umbilical ratio are strong predictors of IUGR and of adverse perinatal outcome in preeclampsia. The MCA PI alone is not a reliable indicator. The combination of umbilical and fetal cerebral Doppler indices may increase the utility of Doppler ultrasound in preeclamptic subjects.     

The clinical value of maternal and fetal Doppler parameters in low-risk postdates pregnancies – a prospective study

Objective: The objective of this study is to determine the clinical significance of maternal and fetal ultrasound Doppler flow indices in postdates pregnancies.

Methods: This prospective study comprised 120 low-risk pregnant women beyond 40 weeks of gestation. All participants underwent Doppler assessment including of fetal middle cerebral artery (MCA), umbilical, and uterine arteries. Perinatal outcomes were recorded and evaluated for possible associations with Doppler flow values. Adverse perinatal outcomes were defined as umbilical cord arterial pH <7.1, Apgar score <7 at 5?min, neonatal admission to a neonatal intensive care unit, and emergency cesarean section due to abnormal intrapartum cardiotocogram

Results: Adverse perinatal outcome rate was 17.5% (n?=?21). Doppler indices of umbilical artery, MCA, uterine artery and the cerebroplacental ratio (CPR) did not differ significantly between pregnant women with and without adverse perinatal outcomes. Neonatal birth weight was found to correlate negatively with umbilical artery Doppler indices, including the peak systolic to end diastolic ratio (p?=?.04), the resistance index (p?=?.02), and the pulsatility index (p?=?.01). Doppler values of the uterine artery, MCA and CPR did not correlate with neonatal birth weight.

Conclusions: The contribution of maternal and fetal ultrasound Doppler to the prediction of adverse perinatal outcomes in low-risk postdates pregnancies is low. Hence, performing routine Doppler examination as part of postdates pregnancy assessments is unlikely to yield significant clinical benefit.     

Understanding the pathophysiology of intra-uterine growth retardation: the role of the 'lower limb reflex' in redistribution of blood flow.

Doppler ultrasound was used to investigate the circulatory redistribution and underlying reflex responses of fetal cardiovascular compensation in 30 small-for-gestational age (SGA) fetuses. The utero-placental bed, umbilical artery and vein, thoracic and abdominal aorta, internal and external cerebral arteries were evaluated. The values were compared to reference ranges constructed from 135 normal pregnancies, correlated to fetal blood gases obtained by cordocentesis and compared to the outcomes. In Group I (mortality and morbidity), all fetuses had loss of end-diastolic frequencies (L-EDF) in the abdominal aorta (100%), but only 20 (87%) and 13 (56%) had L-EDF in the thoracic aorta and umbilical artery respectively. High vascular resistance in the placental bed and low impedance in the middle cerebral and common carotid arteries was found in 14 (61%), 12 (52%) and 20 (87%) fetuses, respectively. In Group II (Healthy infants) two fetuses had high utero-placental vascular resistance and one had brain-sparing. Doppler indices did not always reflect fetal hypoxaemia demonstrating that redistribution in SGA fetuses may not be triggered by a fall in pO2, and that hypoxaemia is an associated pathology but may not be the underlying cause. It is postulated that redistribution in SGA fetuses is regulated by reflex mechanisms (the 'lower limb reflex') which result in severe vasoconstriction in the abdominal aorta, mesentery and carcass, favouring the brain and cardiac muscles. This mechanism explains the good predictive value of L-EDF in the abdominal aorta for poor neonatal outcome (sensitivity, specificity and positive predictive value, all 100%).(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparison of fetal abdominal circumference measurements and Doppler ultrasound in the prediction of small-for-dates babies and fetal compromise

A total of 145 pregnancies clinically suspected of being small-for-dates was studied at presentation with a single measurement of the fetal abdominal circumference and Doppler studies of the umbilical and arcuate arteries. The abdominal circumference measurement gave the best prediction of the small-for-gestational-age (SGA) baby (sensitivity 73%, umbilical artery sensitivity 47%, arcuate artery sensitivity 29%). The umbilical artery measurement gave the best prediction of antenatal fetal compromise; the performance of the tests was compared for a fixed sensitivity of 100% (i.e. all cases of antenatal compromise would be detected), the specificity of the umbilical artery measurement was 77%, abdominal circumference measurement 12% and arcuate artery measurement 2%. In our data, umbilical artery studies were not a sensitive predictor of the SGA baby but they did give an accurate prediction of the potentially compromised SGA fetus.     

Fetal volume blood flow and umbilical artery flow velocity waveform analysis: a comparison

Summary. The estimation of fetal umbilical vein and aortic volume blood flow was compared with umbilical artery flow velocity-time waveform analysis in 42 pregnancies. The volume blood flow measurements were made with a combined linear array B-mode and pulsed Doppler ultrasound system. The umbilical artery flow velocity-time waveform analysis was made with either pulsed or continuous wave 2 MH_zDoppler ultrasound and the systolic/diastolic (A/B) ratio was used as an index of flow resistance. There was no difference when continuous wave was compared to pulsed Doppler ultrasound as a method of recording flow velocity waveforms. Analysis of the umbilical artery flow velocity-time waveform was more sensitive (100%-50%) than the measurement of umbilical vein volume blood flow (ml/kg/min) in the detection of the small-for-gestational age (SGA) fetus. The predictive value of a positive test was higher (71%-45%) while specificity was similar (88%-81%). Descending aortic volume flow was reduced in only one SGA fetus. The increase in umbilical placental downstream resistance (high systolic/ diastolic ratio) was associated with a reduction in the percentage of fetal aortic blood flow directed to the umbilical placental circulation.     

A comparison of fetal abdominal circumference measurements and Doppler ultrasound in the prediction of small-for-dates babies and fetal compromise

Summary. A total of 145 pregnancies clinically suspected of being small-for-dates was studied at presentation with a single measurement of the fetal abdominal circumference and Doppler studies of the umbilical and arcuate arteries. The abdominal circumference measurement gave the best prediction of the small-for-gestational-age (SGA) baby (sensitivity 73%, umbilical artery sensitivity 47%, arcuate artery sensitivity 29%). The umbilical artery measurement gave the best prediction of antenatal fetal compromise; the performance of the tests was compared for a fixed sensitivity of 100% (i. e. all cases of antenatal compromise would be detected), the specificity of the umbilical artery measurement was 77%, abdominal circumference measurement 12% and arcuate artery measurement 2%. In our data, umbilical artery studies were not a sensitive predictor of the SGA baby but they did give an accurate prediction of the potentially compromised SGA fetus.     

Fetal volume blood flow and umbilical artery flow velocity waveform analysis: a comparison

Summary. The estimation of fetal umbilical vein and aortic volume blood flow was compared with umbilical artery flow velocity-time waveform analysis in 42 pregnancies. The volume blood flow measurements were made with a combined linear array B-mode and pulsed Doppler ultrasound system. The umbilical artery flow velocity-time waveform analysis was made with either pulsed or continuous wave 2 MH_zDoppler ultrasound and the systolic/diastolic (A/B) ratio was used as an index of flow resistance. There was no difference when continuous wave was compared to pulsed Doppler ultrasound as a method of recording flow velocity waveforms. Analysis of the umbilical artery flow velocity-time waveform was more sensitive (100%-50%) than the measurement of umbilical vein volume blood flow (ml/kg/min) in the detection of the small-for-gestational age (SGA) fetus. The predictive value of a positive test was higher (71%-45%) while specificity was similar (88%-81%). Descending aortic volume flow was reduced in only one SGA fetus. The increase in umbilical placental downstream resistance (high systolic/ diastolic ratio) was associated with a reduction in the percentage of fetal aortic blood flow directed to the umbilical placental circulation.