Umbilical Artery Velocity Waveforms Research Articles

Splenic artery velocity waveforms in small-for-gestational-age fetuses: Relationship with pH and blood gases measured in umbilical blood at cordocentesis

OBJECTIVE: Our purpose was to relate velocity waveforms from the splenic artery with pH and blood gas levels measured at cordocentesis in small-for-gestational-age fetuses and to compare the diagnostic efficiency of splenic artery waveforms with that of other fetal arterial and venous vessels in predicting acid-base status. STUDY DESIGN: Cross-sectional recordings from the splenic artery were obtained by color and pulsed Doppler techniques in 316 appropriately grown fetuses, 12 small-for-gestational-age fetuses with normal umbilical artery velocity waveforms (group 1), and 30 small-for-gestational-age fetuses with abnormal umbilical artery velocity waveforms (group 2). Measurements of splenic artery pulsatility index values in small-for-gestational-age fetuses were compared with those of appropriate-for-gestational-age fetuses. Associations of splenic artery pulsatility index with Po 2, Pco 2, and pH values measured at cordocentesis were examined and compared with those of umbilical artery, middle cerebral artery, and inferior vena cava. RESULTS: In appropriately grown fetuses pulsatility index values from the splenic artery decrease with advancing gestation ( r = 0.51, p < 0.0001). Splenic artery pulsatility index values are lower in group 2 ( p < 0.001) but not in group 1 small-for-gestational-age fetuses ( p = 0.211). The amplitude of the decrease in the pulsatility index is significantly associated with fetal hypoxemia ( r = 0.646, p < 0.001), acidemia ( r = 0.593, p < 0.001) and hypercapnia ( r = 0.577, p < 0.001). However, logistic regression demonstrates that hypoxia is better predicted by middle cerebral artery pulsatility index, whereas hypercapnia and acidosis are more closely associated with the percent of reverse flow in inferior vena cava. CONCLUSION: A decrease in the splenic artery pulsatility index occurs in small-for-gestational-age fetuses in the presence of abnormal pH and blood gas values, but a more accurate assessment of acid-base status may be obtained with the study of the middle cerebral artery and inferior vena cava.(Am J Obstet Gynecol 1997;176:300-7.)

An automated intelligent diagnostic system for the interpretation of umbilical artery Doppler velocimetry

The objective is to develop an automated intelligent diagnostic system for the interpretation of umbilical artery velocity waveforms. An ultrasound instrument with pulsed-wave Doppler is connected to a microcomputer by means of a frame grabber. After data acquisition, umbilical Doppler velocimetry is handled as a pattern recognition (feature extraction and classification) and decision-making problem. Automated image processing (enhancement, smoothing/thresholding and edge detection) and analysis are used for feature extraction. Six waveform indices obtained by feature extraction are used as input layer to vector quantization which classifies waveforms into six groups. A clinical decision is assigned to each group by the medical expert. Our system is trained by 278 and 380 waveform images of 94 normal and 157 high risk pregnancies, respectively. The system was tested with 193 and 61 images of normal and risky pregnancies; it was demonstrated that sensitivity and specificity of the system are 54.1% and 80.3%, respectively.

Fetal pH value determined by cordocentesis: an independent predictor of the development of antepartum fetal heart rate decelerations in growth retarded fetuses with absent end-diastolic velocity in umbilical artery.

Objective of this study was to establish the relationship in growth retarded fetuses between acid-base status in fetal blood obtained by cordocentesis and time interval between blood sampling and occurrence of antepartum heart rate late decelerations. Eighteen growth retarded fetuses scheduled for cordocentesis were considered for this study. All fetuses were free from structural and chromosomal abnormalities, characterized by absent end diastolic velocity waveforms in umbilical artery and later delivered for the development of antepartum heart rate late decelerations. Regression analysis showed that the time interval between cordocentesis and delivery was significantly related to pO2 (r = 0.46; p < or = 0.05) and pH (r = 0.57; p < or = 0.01) delta values but not with pCO2 values. Stepwise multiple regression analysis demonstrated that the severity of fetal acidosis significantly and independently predicted the length of this time interval even after controlling for confounding variables such as pO2 values, gestational age, presence of hypertension, or umbilical vein pulsations. The knowledge of this relationship may be useful in the clinical management of growth retarded fetuses.

The value of fetal arterial, cardiac and venous flows in predicting pH and blood gases measured in umbilical blood at cordocentesis in growth retarded fetuses.

To assess the value of Doppler indices, calculated from fetal arterial peripheral vessels, cardiac outflow tracts and venous vessels, in the identification of acidaemia, hypercapnia and hypoxaemia as determined by pH and gas analysis of fetal blood obtained by cordocentesis in growth retarded fetuses. Doppler measurements were taken from umbilical artery, thoracic descending aorta, renal artery, middle cerebral artery, cardiac outflow tracts, inferior vena cava and ductus venosus immediately before cordocentesis. Logistic regression and receiver-operator characteristic curve analysis were performed to examine the relation between Doppler indices and acid-base status. Tertiary centre for fetal medicine. Forty-eight growth retarded fetuses fulfilling these criteria for inclusion: 1. absence of chromosomal and structural anomalies; 2. an abdominal circumference or ultrasonographic estimated fetal weight less than the 5th centile; 3. presence of abnormal velocity waveforms in umbilical artery; and 4. postnatal confirmation of a birthweight below the 5th centile and absence of structural anomalies. The percentage of reverse flow in inferior vena cava was a more closely related variable for acidaemia (chi 2 = 29.69; P < or = 0.001) and hypercapnia (chi 2 = 12.86; P < or = 0.001) than the other Doppler indices. Hypoxaemia was better predicted by the pulsatility index from middle cerebral artery (chi 2 = 15.31; P < or = 0.001). The analysis of velocity waveforms from inferior vena cava and middle cerebral artery can be used to predict acid-base status in growth retarded fetuses secondary to placental insufficiency. This may lead to a more accurate antepartum monitoring of such fetuses.

Umbilical artery flow velocity waveforms in monoamniotic twins with cord entanglement

Monoamniotic twins with ultrasonographic evidence of umbilical cord entanglement present a management challenge in the antepartum period. We report two pregnancies with monoamniotic twins and ultrasonographic evidence of cord entanglement in which longitudinal Doppler flow velocity waveforms of the umbilical and middle cerebral arteries were obtained. A notch in the umbilical artery velocity waveform was noted in one twin member at 33 weeks' gestation and in both twin members of the other pregnancy at 31 weeks' gestation. Worsening of the umbilical artery velocity waveform notch with advancing gestation was noted in one fetus. The presence of a notch in the umbilical artery velocity waveform may reflect hemodynamic alterations in the fetal-placental circulation secondary to narrowing of the umbilical vessels involved in cord entanglement. This Doppler finding may be useful in the antepartum management of these pregnancies.

Clinical significance of absent or reversed end diastolic velocity waveforms in umbilical artery

International Journal of Gynecology & ObstetricsVolume 50, Issue 3 p. 320-320 Citations from the literature (including the russian literature) pregnancy and delivery Clinical significance of absent or reversed end diastolic velocity waveforms in umbilical artery Karsdorp V.H.M.; Van Vugt J.M.G.; Van Geijn H.P.; Kostense P.J.; Arduini D.; Montenegro N.; Todros R. NLD Lancet 1994 344/8938 (1664–1668) First published: September 1995 https://doi.org/10.1016/0020-7292(95)92800-GAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume50, Issue3September 1995Pages 320-320 RelatedInformation

The influence of the site of Doppler recording on umbilical artery pulsatility index during the first trimester

The aim of our study was to determine the pulsatility index (PI) of the umbilical artery velocity waveform obtained from the fetal insertion, the placental insertion and a free floating loop of the umbilical cord. This was a prospective study involving 60 consecutive singleton pregnancies undergoing ultrasound examination between 10 and 13 weeks' gestation. Doppler measurements were obtained transvaginally from the placental and the fetal abdominal insertion, and from a free floating loop of umbilical cord. Chromosomal abnormalities and structural malformations detected by ultrasound were excluded. A multi-way analysis of variance did not show significant differences between the measurements of umbilical PI at the different sites of the umbilical cord and Pearson's coefficient showed an excellent correlation between them. No significant intra- and interobserver differences were found. In conclusion, measurements of Doppler velocimetric indices of the umbilical artery during the first trimester are not influenced by the recording site and these recordings are reproducible at this stage of gestation.

Clinical significance of absent or reversed end diastolic velocity waveforms in umbilical artery

Summary Doppler ultrasound provides a non invasive method to assess fetal haemodynamics. We looked at the outcome of doppler velocimetry of the umbilical artery in three groups of pregnancies: those with positive end diastolic velocities (PED; n=214), absent end diastolic velocities (AED; n=178) and reversed end diastolic velocities (RED; n=67). We collected our data from 9 European centres. Logistic regression showed that compared with pregnancies with hypertension only, pregnancies complicated by intra uterine growth retardation (IUGR) had a higher risk of developing absent or reversed end diastolic velocity waveforms (ARED) flow. ARED flow in the umbilical artery (odds ratio: OR=3·1). Pregnancies complicated by both IUGR and hypertension had an even higher risk (OR=7·4). Maternal age and smoking habits did not influence the risk of developing ARED flow. The overall perinatal mortality rate was 28%. Significantly more neonates in the ARED flow group needed admittance to the neonatal intensive care unit (PED group 60%, AED group 96%, RED group 98%). The OR for perinatal mortality in pregnancies complicated by AED flow was 4·0 and in RED flow was 10·6, compared with PED flow, even after adjustment for menstrual age. ARED flow in the umbilical artery did not influence the risk of respiratory distress syndrome or necrotising enterocolitis of the neonate, but ARED flow significantly influenced the risk of cerebral haemorrhage, anaemia, or hypoglycaemia. We advise that pregnancies complicated by IUGR and/or hypertension should be followed up with doppler velocimetry to trace utero-placental problems as early as possible. A caesarean section is recommended in all pregnancies complicated by ARED flow if the gestational age and predicted neonatal weight can be handled by the local neonatal intensive care unit.

Role of Doppler sonography in fetal/maternal medicine

Doppler velocimetry of umbilical, fetal, and uteroplacental vessels provides important information on fetal and uterine hemodynamics and has therefore become one of the most dynamic areas of perinatal research. Examinations of umbilical artery velocity waveforms have gained recognition as a valuable clinical method of fetal surveillance in risk pregnancies. Pathological Doppler findings, especially the finding of absent or reverse end-diastolic (ARED) flow velocity, are associated with fetal hypoxia and adverse outcome of pregnancy. The first follow-up studies indicate that abnormal Doppler findings are associated with impaired postnatal neurological development. Velocimetry of the fetal middle cerebral artery provides important information on redistribution of fetal blood flow in hypoxia; its place in clinics remains to be established. Similarly, more studies are needed to evaluate the use of Doppler velocimetry in labor. Possibly, the Doppler method may facilitate the interpretation of equivocal cardiotocography (CTG) tracings. New evidence has been collected on the correlation between hemodynamic findings and the morphology of the placenta and the placental bed. One of the very important applications of Doppler velocimetry is the evaluation of pharmacological effects on fetal circulation of drugs used for treatment in pregnancy and labor.

Reverse end-diastolic umbilical artery velocity in a case of intrauterine fetal death at 14 weeks' gestation

A case of intrauterine fetal death at 14 week's gestation in a mother with systemic lupus erythematosus is described. Doppler ultrasonography performed within 24 hours before fetal death showed reverse end-diastolic flow velocities on umbilical artery velocity waveforms. The placental alteration causing this early gestation is discussed.

Vascular resistance and the umbilical arterial velocity waveforms

Vascular resistance and the umbilical arterial velocity waveforms

Neonatal outcome following pregnancy complicated by abnormal umbilical arterial velocity waveforms : M. McDonnell, V. Serra Serra, G. Caffney, C.W.G. Redman and P.L. Hope, Department of Paediatrics and Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Oxford, OX3 9DU (UK)

Neonatal outcome following pregnancy complicated by abnormal umbilical arterial velocity waveforms : M. McDonnell, V. Serra Serra, G. Caffney, C.W.G. Redman and P.L. Hope, Department of Paediatrics and Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Oxford, OX3 9DU (UK)

Changes in flow velocity waveforms in umbilical and uterine artery following haemodialysis. Case report.

Changes in flow velocity waveforms in umbilical and uterine artery following haemodialysis. Case report.

Umbilical artery velocity waveforms in early pregnancy: a transvaginal color Doppler study.

In a cross-sectional study, umbilical artery velocity waveforms were recorded in 214 low-risk pregnancies at 7 weeks to 16 weeks, menstrual age, by means of transvaginal color and pulsed Doppler ultrasonography. In all the cases studied, end diastolic velocities were absent until the 10th week. From this age onward end diastolic velocities were present in a percentage of pregnancies, progressively increasing with gestation and reaching 100% at 15 weeks. Similarly, the percentage of cardiac cycles in which end diastolic velocities were absent progressively decreased with advancing menstrual age. The normal range for the pulsatility index was constructed and a quadratic function was found to optimally fit its fall during gestation. No differences in pulsatility index values were found at these menstrual ages in 12 pregnancies that later developed intrauterine growth retardation and/or pregnancy-induced hypertension, suggesting that placental alterations causing abnormalities in umbilical velocity waveforms occur later in gestation.

Fetal umbilical artery velocity waveforms and subsequent neonatal outcome

Flow velocity waveforms (FVWs) from the fetal umbilical artery were recorded from 2178 pregnant women over a 6-year period. All of them had an obstetric factor indicating increased risk of fetal compromise. A total of 6749 studies was recorded. The systolic diastolic (AB) ratio was measured and classified as normal (less than 95th centile), elevated (95-99th centile), high (greater than 99th centile) or extreme (absent diastolic flow). The results of these studies have been related to subsequent fetal and neonatal outcome. An abnormal umbilical artery FVW was associated with shorter gestation and infants with lower birthweight, shorter length and lower ponderal index. There was a highly significant association between an abnormal FVW and the birth of an infant small for gestational age. The significance of the association increased with the increased abnormality of the umbilical artery FVW and this was independent of gestational age. Preterm infants associated with high or extreme AB ratios spent twice as long in the neonatal nursery than those with normal AB ratios. Analysis of 794 pregnancies studies serially indicated that an abnormal FVW in which the AB ratio was increasing, in contrast to a decreasing AB ratio, predicted a poor outcome for both size at birth and duration of neonatal intensive care. We conclude that in high risk pregnancy Doppler umbilical artery FVW studies predict the most compromised fetuses in terms of growth retardation and requirements for neonatal intensive care.

The Effect of Lateral Tilt on Maternal and Fetal Hemodynamic Variables

We measured maternal blood pressure and heart rate, fetal heart rate, and umbilical artery velocity waveforms in 25 healthy women placed in the supine and in both right and left 5 degrees and 10 degrees lateral tilt positions. Although we found no significant difference among these variables in the various maternal positions, two of 25 women became hypotensive and symptomatic in the supine and 5 degrees tilt positions. Because we could not predict which women would become symptomatic, we recommend lateral tilt of all pregnant women during operative procedures beyond 20 weeks' gestation, including those in the lithotomy position for vaginal delivery.

Umbilical Artery Waveforms in Triplet Pregnancy

Twenty patients with triplet pregnancies underwent continuous-wave Doppler ultrasound umbilical artery waveform studies as part of a multiple-pregnancy surveillance program. One or more infants was small for gestational age in nine of these triplet pregnancies. In all of these cases, at least one abnormal umbilical artery velocity waveform was present. Two infants were stillborn, and both had a grossly abnormal umbilical artery waveform (absent diastolic flow) recorded consistently for several weeks before fetal death. The use of umbilical artery Doppler studies may delineate those triplet pregnancies in which more intensive fetal surveillance is appropriate.

Umbilical artery blood flow velocity waveforms in pregnancy complicated by diabetes mellitus

Umbilical artery blood velocity waveforms were recorded by a pulsed Doppler system in the third trimester of pregnancy in 16 diabetic women (12 class B, 1 class C, 3 class D) and the waveforms were analysed for resistance index (RI = peak systolic velocity minus end diastolic velocity/peak systolic velocity). There was no significant correlation between the RI values and either serum glucose (r = 0.385) or fructosamine levels (r = 0.380). However, the RI values were raised in two cases with serum glucose levels of over 300 mg/dl. With a fall in serum glucose levels, the RI values returned to the normal range. No abnormal umbilical artery velocity waveforms were found when the serum glucose level was below 200 mg/dl.

Umbilical Artery Pulsatility Index and Placental Vascular Resistance during Acute Hypoxemia in Fetal Lambs

The effect of hypoxemia on the pulsatility index (PI) of the umbilical artery flow velocity waveform and placental vascular resistance was studied. Fetal hypoxemia was induced by maternal breathing of a low-oxygen gas mixture. Umbilical venous blood flow was measured with an electromagnetic flowmeter. Placental vascular resistance (PVR) was defined as the ratio perfusion pressure (mean arterial pressure minus umbilical venous pressure) and umbilical blood flow. Umbilical artery velocity waveforms were obtained by a 5-MHz pulsed Doppler device around one umbilical artery in 4 lambs and by a transcutaneous 4-MHz continuous wave Doppler transducer in 3 lambs. Fetal arterial oxygen content was lowered from 2.28 +/- 0.18 to 0.93 +/- 0.15 mM (p less than 0.05), while pCO2 and pH remained unchanged. Control values of the hemodynamic variables were compared with values during deepest hypoxemia. Fetal heart rate, mean arterial and umbilical venous pressure, PVR and the umbilical artery PI did not significantly change, whereas umbilical blood flow increased from 436 +/- 64.7 to 491 +/- 65.9 ml/min (p less than 0.05) during deepest hypoxemia. Individual regression analysis, however, showed a significant inverse correlation of umbilical venous pressure whereas PVR had a positive correlation with actual oxygen content. It is concluded that acute fetal hypoxemia slightly decreases PVR, but does not affect the umbilical artery PI in sheep. Decreasing fetal oxygenation is associated with an increase in pressure in the umbilical vein.

A study on the fetal umbilical artery doppler blood flow velocity waveforms in normal pregnancy

Noninvasive techniques for antenatal detection of the fetal development and well-being such as biophysical profile, non-stress and stress test remain major challenges in modem obstetric practice. To obtain and analyze umbilical artery velocity waveform by pulsed-wave doppler ultrasound, a total of 160 determinations were carried out on 157 normal pregnant women between 16th to 41st week gestation. The ratio of peak systolic to end-diastolic flow velocity(S/D ratio), pulsatility index and resistance index were measured as indices of the resistance in feto-placental circulation. The results were as follows : As gestation advances, the, mean values for peak systolic and end-diastolic velocities raised progressively. As gestation advances, the mean values for the S/D ratio declined progressively, exhibiting high diastolic flow velocity caused by low resistance. Pulsatility index, and resistance index were also declined progressively, as gestation advances. The analysis of umbilical artery blood flow velocity waveforms provides a new noninvasive technique to evaluate fetal development and well-being, and may be expected a reliable method for assessment of fetal life.