Doppler assessment of the fetal asphyxia in pregnancies complicated by gestational hypertension and intrauterine growth retardation

OBJECTIVES: Gestational hypertension is associated with a high morbidity for both mother and fetus. Doppler ultrasound has allowed the fetal circulation to be examined. Now it is possible to monitor the response of the fetal circulation to hypoxia. DESIGN: The aim of this study was to determine flow patterns in fetal circulation from pregnancies complicated by gestational hypertension and intrauterine growth restriction. MATERIALS AND METHODS: The investigation included 23 fetuses with signs of the gestational hypertension and intrauterine growth restriction. We evaluated cerebral-placental ratio (CPR) and pulsation index (PI) in the middle cerebral artery (MCA) and the umbilical artery (UA). We also evaluated flows in umbilical vein. RESULTS: We observed abnormal flow pattern in all cases of analyzing fetuses. The most common abnormal flow was vein pulsation (48%). CONCLUSIONS: All analyzing fetuses shown signs of the hypoxia. Present of the umbilical vein pulsation or decompensate of the brain sparing effect is closely related o increased perinatal mortality.     

Multivascular Doppler surveillance in high risk pregnancies

Objectives: Analysis of fetal arterial and venous Doppler predictability for adverse perinatal outcome. Methods: Blood flow in the uterine, umbilical and middle cerbral arteries, umbilical vein, ductus venosus and Galen vein were examined with in 72?h of delivery in 88 high-risk pregnancies. The managing clinicians were only informed about the results of the umbilical artery Doppler. The Doppler results were correlated to adverse perinatal outcome. Results: Doppler abnormalities were seen in both preterm and term pregnancies. Umbilical venous pulsations (n?=?13) were strongly correlated to Apgar score <7 at 5?min, abnormal blood gases, need for ventilation assistance and operative delivery for fetal distress. Twenty-four fetuses had brain sparing in the middle cerebral artery, and forty-five had abnormal umbilical artery Doppler. These were correlated to admission in the neonatal intensive care unit, operative delivery and prematurity. Brain sparing in middle cerebral artery was also correlated to ventilation disturbances in the newborns. Abnormal ductus venosus blood velocity was only seen in 9 cases and not related to adverse outcome. Galen vein pulsations (n?=?26) seem to appear earlier than pulsations in the umbilical vein and were not related to adverse outcome. conclusion: Umbilical vein pulsations were better correlated to adverse perinatal outcome than were other Doppler findings including ductus venosus.     

Association of umbilical venous with inferior vena cava blood flow velocities

The fetal cardiac and placental circulations are interconnected through the umbilical venous and arterial vasculature. We hypothesized that alterations in umbilical venous blood flow velocities are present in fetuses with abnormal umbilical arterial circulation, and further, that changes in inferior vena cava blood flow velocities occur with, and might explain, these variations in umbilical venous blood flow velocities. Umbilical venous and inferior vena cava blood flow velocities were examined in 15 normal fetuses and in 59 fetuses with abnormalities that included absent end-diastolic umbilical artery blood flow velocities (N = 21) or abnormal heart rates (N = 27). Inferior vena cava velocities were also analyzed in 11 other fetuses with anomalies or known growth or placental abnormalities who had abnormal umbilical venous blood flow velocities. In normal fetuses, variations in umbilical venous velocities occurred during fetal activity or with fetal breathing; however, no variation in velocity corresponded with heart rate. Eleven of 21 fetuses with absent end-diastolic velocities in the umbilical artery demonstrated decreases in umbilical venous velocities ("venous pulsations") during arterial diastole. Blood flow velocities in the reverse direction, from the right atrium into the inferior vena cava with atrial contraction, were significantly greater in these fetuses than in those without umbilical venous pulsations (27.5 +/- 14.9% and 7.5 +/- 5.7% of total forward flow velocity, respectively; P less than .001). Venous pulsations were also seen in fetuses with abnormally fast or slow heart rates; reverse flow with atrial contraction in the inferior vena cava was likewise greater than normal in these fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Doppler assessment of umbilical artery, thoracic aorta and middle cerebral artery in the management of pregnancies with growth restriction

BACKGROUND: The aim of the study was to determine the best use of information obtained from Doppler studies of umbilical artery, thoracic aorta and middle cerebral artery in the management of pregnancies with growth restriction. METHODS: The study group consisted of 100 pregnant women with intrauterine growth restricted fetuses. Doppler flow velocity waveforms were obtained from the umbilical artery, middle cerebral artery and thoracic aorta. The pregnancies were grouped according to the umbilical artery Doppler results. There were 29, 30 and 41 fetuses with normal and high PI (pulsatility index), and absent end-diastolic velocity (AEDV) in the umbilical artery, respectively. RESULTS: Birth weight and umbilical vein pH at birth significantly decreased and perinatal mortality rates significantly increased with the worsening of the diastolic flow in the umbilical artery (p<0.01). Increased umbilical artery PI was significantly associated with increased thoracic aorta PI and decreased middle cerebral artery PI (r=0.75 and -0.55, p<0.01 respectively). Perinatal mortality due to fetal asphyxia in fetuses with AEDV in the umbilical artery and in both the umbilical artery and thoracic aorta was 39.5% and 50%, respectively. Detection of AEDV in the thoracic aorta was found to be the most significant predictive factor of perinatal deaths. CONCLUSIONS: The degree of abnormality of the Doppler findings parallels the severity of fetal compromise. Growth restricted fetuses with AEDV detected both in the umbilical artery and thoracic aorta are severely compromised and time gained in utero has no benefit for these fetuses.     

Arterial and ductus venosus Doppler in fetuses with absent or reverse end-diastolic flow in the umbilical artery: longitudinal analysis

OBJECTIVE: To evaluate alterations of arterial and ductus venosus blood flow velocities during deterioration and their interdependence. METHODS: 37 high-risk pregnancies complicated by umbilical absent or reverse end-diastolic flow velocities (AREDV) were monitored by measurement of the pulsatility index of the umbilical artery, middle cerebral artery and ductus venosus waveforms. RESULTS: The mean observation period was 16.5 days. There was a significant change in the pulsatility of waveforms in all vessels over the observation period. Compared with the ductus venosus, pulsatility of waveforms in the middle cerebral artery diverged from the normal range 2.2 weeks earlier. Increase in pulsatility in the umbilical artery was concomitant with venous but not with cerebral flow alterations. In addition, there was a correlation between the increase of venous but not arterial pulsatility and perinatal acidemia. Variability of pulsatility index values of the umbilical artery and the ductus venosus but not of the middle cerebral artery increased towards delivery. CONCLUSIONS: Ductus venosus Doppler allows detection of further deterioration in centralized fetuses with umbilical AREDV. However, striking short-term variability has to be taken into account when considering this parameter.     

Association of severe placental insufficiency and systemic venous pressure rise in the fetus with increased neonatal cardiac troponin T levels

OBJECTIVE: The aim of this study was to test the hypothesis that severe placental insufficiency and a rise in fetal systemic venous pressure are associated with fetal myocardial cell damage, which in turn leads to increased neonatal troponin T levels. STUDY DESIGN: Sixty-six neonates born after uncomplicated pregnancy and delivery were included in the control group. Study groups 1 and 2 consisted of 32 and 5 neonates, respectively, born to women with hypertensive disorder. In study group 1 the fetal intra-abdominal portion of the umbilical vein showed normal nonpulsatile blood flow pattern in every case. In study group 2 all the fetuses had atrial pulsations in the intraabdominal umbilical vein. After delivery blood samples were collected from the umbilical arteries, and cardiac troponin T concentrations were measured with commercially available enzyme-linked immunosorbent assay kits. A clinically significant troponin T level was set at >/=0.10 ng/mL. RESULTS: In study group 1 the maternal main uterine arterial blood flow pattern was normal in 30 cases and abnormal in 2 cases. Umbilical artery blood velocity waveforms were normal in 26 fetuses, 4 fetuses had a decreased diastolic blood flow, 1 fetus had an absent diastolic blood flow pattern, and 1 fetus had a retrograde diastolic blood flow pattern. In study group 2 maternal uterine arterial Doppler findings were abnormal in every case, and all the fetuses had retrograde diastolic blood flow pattern in the umbilical artery. Neonatal troponin T levels were <0.10 ng/mL in the control group (0-0.14 ng/mL) and in study group 1 (0-0.16 ng/mL), except for 1 case in each group. Every neonate in study group 2 had a troponin T level >0.10 ng/mL, with the range from 0.11 to 0.35 ng/mL. In study group 2 troponin T concentrations were significantly higher (P <.0001) than in either the control group or study group 1. CONCLUSION: Neonatal troponin T levels are not clinically significantly increased in normal pregnancies and in pregnancies complicated by maternal hypertensive disorder but with normal fetal umbilical venous return. Neonatal troponin T concentrations are significantly increased in the presence of abnormal umbilical venous return, which indicates myocardial cell damage.     

Effect of an increase of the hematocrit on middle cerebral artery peak and umbilical vein maximum velocities in anemic fetuses

OBJECTIVE: To measure the effects of acute large increases of the hematocrit on fetal peak arterial and maximum venous blood flow velocities. METHODS: Middle cerebral artery peak flow velocities and umbilical vein maximum flow velocities were measured before, immediately after, and 12-24 h after intrauterine transfusions. All measurements were standardized for gestational age. RESULTS: Complete measurements were obtained at 60 intrauterine transfusions. The mean hematocrit before intrauterine transfusion was 0.19 l/l and after 0.40 l/l. The middle cerebral artery peak flow velocity decreased immediately after transfusion in 59 of the 60 cases. There was a rise in umbilical vein maximum flow velocity immediately after intrauterine transfusion in 37 of the 60 cases. The sensitivity of middle cerebral artery peak flow velocity for severe anemia before intrauterine transfusion was 54% and the specificity 57%. The sensitivity of umbilical vein maximum flow velocity for severe anemia before intrauterine transfusion was 67% and the specificity 57%. CONCLUSIONS: An acute large increase of the fetal hematocrit significantly decreases middle cerebral artery peak flow velocity. The effect on umbilical vein maximum velocity is, however, unpredictable.     

Cerebral venous blood flow in growth restricted fetuses with an abnormal blood flow in the umbilical artery before 32 weeks of gestation

Objective

To evaluate the brain venous circulation in fetuses with severe intrauterine growth restriction (IUGR) before 32 weeks of gestation.

Study design

Fifty fetuses with severe IUGR diagnosed between 27 and 32 weeks of gestation and 50 appropriate-for-gestational age (AGA) fetuses matched by gestational age were evaluated. IUGR fetuses were classified according to their hemodynamic deterioration pattern in relation to the Doppler examination of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV). The fetal venous brain blood flow was evaluated in the vein of Galen (VG), superior sagittal (SS), straight and transverse venous sinuses.

Results

Only the transverse sinus (TS) showed a significant reduction in the pulsatility index (PI) values in IUGR fetuses. All other veins showed similar PI values between IUGR and AGA fetuses. All cerebral veins of IUGR fetuses showed significantly increased maximum and mean velocities. All these findings did not change in relation to the hemodynamic IUGR deterioration. In nearly all normal and all IUGR fetuses, a pulsatile blood flow pattern was observed in the straight and transverse sinuses, whereas an increased pulsatile pattern in the VG and in the SS was noted in IUGR fetuses.

Conclusion

Brain venous blood flow in IUGR fetuses shows an increment in the maximum and mean velocities of all veins and a reduction in the PI in the transverse sinus.     

Adrenomedullin is increased in the fetoplacental circulation in intrauterine growth restriction with abnormal umbilical artery waveforms

OBJECTIVE: To examine whether adrenomedullin, a novel vasoactive peptide produced by the placenta, participates in the uteroplacental hemodynamic alterations in intrauterine growth restriction, we studied the correlation between adrenomedullin levels and fetoplacental blood flow. STUDY DESIGN: Maternal and umbilical blood samples were collected in pregnancies complicated by intrauterine growth restriction with abnormal umbilical artery Doppler findings and in control pregnancies. Adrenomedullin levels were measured by means of a specific radioimmunoassay, and flow velocimetry waveforms were recorded from uterine, umbilical, and fetal middle cerebral arteries. RESULTS: Mean adrenomedullin values in umbilical plasma were higher (P <.05) in patients with intrauterine growth restriction (63.7 +/- 34.2 pg/mL; n = 16) than in control subjects (38.1 +/- 14.8 pg/mL; n = 16). A significant correlation was found between maternal adrenomedullin levels and umbilical artery pulsatility index. Moreover, fetal adrenomedullin concentrations correlated negatively with middle cerebral artery pulsatility index and positively with umbilical artery pulsatility index/middle cerebral artery pulsatility index ratio. CONCLUSION: This study provides evidence that adrenomedullin is increased in fetuses with intrauterine growth restriction in response to reduced uteroplacental blood flow and suggests that it may participate in the fetal hemodynamic modifications.     

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.     

Phasic blood flow patterns in the common umbilical vein of fetal sheep during umbilical cord occlusion and the influence of autonomic nervous system blockade

The blood flow pattern in the common umbilical vein is under normal conditions nonpulsatile in contrast to the flow in the fetal inferior vena cava. We observed pulsatile flow patterns in the common umbilical vein of fetal lambs during changes in the fetal hemodynamic equilibrium. These pulsations may influence the mixing of oxygen-rich ductus venosus blood and oxygen-poor inferior vena cava blood. This study deals with the phasic changes in umbilical venous blood flow during cord occlusion. The experiments were performed in eight chronically instrumented fetal lambs between 114 and 133 days gestation (term 146 days). Umbilical venous blood flow was measured with an electromagnetic flow transducer around the intraabdominal common part of both umbilical veins. The fetuses were provided with catheter in the fetal abdominal aorta and with electrodes for monitoring arterial blood pressure and heart rate. Occlusion of the umbilical cord was performed by means of an inflatable balloon occluder around the total cord (occlusion time 20 to 90 seconds). Occlusions were performed in fetuses with an intact autonomic nervous system and after blockade of the alpha-adrenergic, beta-adrenergic or cholinergic part of the autonomic nervous system.     

Relationship between Doppler velocimetry at middle cerebral artery and umbilical artery and status of newborn

Aim of investigations was qualification of account between Doppler parameters in estimation of fetal state. Investigations one passed on 30 fetuses and newborn children in pregnancies brought. Doppler parameters one priced at use of sonographic device Toshiba SSH 140 A/G and searchers of type convex about working frequency 3.75 MHz. Following Doppler flow blood parameters were analyzed: maximum blood speed (V1) average blood speed (V2) and minimum blood speed (V3), systolic/diastolic ratio (S/D), resistance index (RI), pulsatile index (PI) and proper flow in umbilical cord vein (MF) in following dishes of feto-placental circulation: middle cerebral artery (MCA) and umbilical cord artery (UA). Acid-base equilibrium and gasometry of blood in umbilical cord dishes one marked at use of device Ciba-Corning 278 Blood Gas System and parameters of oxygenation of blood at use of device Ciba-Corning 270 CO-OXIMETER. At new-born children one priced pH-metry (pH) and gasometry (pO2, pCO2, BAA) in blood umbilical cord arterial and venous were measured. The newborn children were estimated by Apgar score. There were following essential statistical correlations between Doppler parameters of fetal blood flow and with parameters of acid-base equilibrium of new-born child: 1/ between V2 and V3 in UA and with supply of rules (BAA) in UV (p = 0.027; p = 0.009) and UA (p = 0.035; p = 0.003) and venous pH (p = 0.022; p = 0.009); 2/ between RI in UA and BAA in UV (p = 0.006) and UA (p = 0.010); 3/ between PI in UA and BAA in UV (p < 0.0001) and UA (p < 0.0001) and pH venous (p < 0.0001). We can conclude that Doppler investigations only by measure of parameters of blood flow in middle cerebral artery and umbilical artery in expectation of state of birth new-born child priced across parameters of acid-base equilibrium and Apgar score are not very useful, however they are helpful.     

Placental ischemia and changes in umbilical and uteroplacental arterial and venous hemodynamics

Objective: To relate Doppler velocimetry findings in fetoplacental and uteroplacental circulation to placental histomorphology. Material and methods: In 14 uncomplicated and 31 high-risk pregnancies Doppler velocimetry was performed in umbilical artery and vein, and in maternal uterine veins and arteries during the second half of gestation. Histopathology of the placentas was examined, especially for signs of ischemia and inflammation. Results: All fetuses in uncomplicated pregnancies had normal flow velocity waveforms in umbilical artery; in the high-risk group, 18 fetuses had abnormal flow (increased PI or absent/reverse end-diastolic flow). The latter group had more often high ischemic score and infarctions in the placenta than found in pregnancies with normal umbilical artery flow (p?<?0.001 and p?=?0.02, respectively). Similarly, the abnormal uterine artery flow pattern (uterine artery score 3–4) occurred more often with high ischemic score and placenta infarctions (p?<?0.001 and p?<?0.001, respectively). No significant associations were found between the uterine venous flow type and placental ischemia. Conclusion: Placental ischemic morphological changes were associated with Doppler ultrasound signs of increased resistance to arterial blood flow, both on the fetal and maternal sides of the placenta. No significant relation to the uterine venous flow velocities was found.     

Blood velocity in the fetal vein of Galen and the outcome of high-risk pregnancy

BACKGROUND: Pulsation in the flow velocity waveform in the umbilical vein is related to perinatal mortality but the flow velocity waveform in the fetal vein of Galen is normally even and without fluctuation. OBJECTIVES: To establish whether blood flow velocity pulsations in the vein of Galen in high-risk pregnancies are related to outcome. STUDY DESIGN: The vein of Galen was located by colour Doppler ultrasound in 102 pregnancies complicated by severe pregnancy-induced hypertension. The blood velocity waveform was recorded by pulsed Doppler within 2 days of delivery and the presence pulsations related to pregnancy outcome, including emergency operative intervention and neonatal distress. Umbilical artery and vein and uterine artery blood flow velocity waveform were also recorded at the same time. The clinicians managing the women were unaware of the venous flow results. RESULTS: Pulsation were present in the vein of Galen in 68 cases and in the umbilical vein in 21. Both were significantly related to adverse outcome. Pulsations in the vein of Galen were seen in all seven perinatal deaths. CONCLUSIONS: Since umbilical venous pulsation are a late sign of fetal compromise, and pulsations in the vein of Galen seem to appear earlier, thus being an intermediate sign of fetal compromise that might be of great value for fetal surveillance.     

Umbilical artery N-terminal peptide of proatrial natriuretic peptide in hypertensive pregnancies and fetal acidemia during labor

OBJECTIVE: To assess the activity of the human fetal atrial natriuretic peptide system in hypertensive pregnancies with and without signs of increased fetal systemic venous pressure and in pregnancies complicated by fetal acidemia during labor. METHODS: Umbilical artery plasma N-terminal peptide of proatrial natriuretic peptide concentrations were measured in neonates by radioimmunoassay. The control group consisted of 50 neonates with uncomplicated gestation and labor. In group 1, there were 22 newborns of hypertensive pregnancies. Doppler ultrasonography showed abnormal umbilical artery blood velocity waveform in five cases and normal nonpulsatile umbilical vein blood velocity profile in every case. Group 2 consisted of five newborns of pregnancies complicated by maternal hypertensive disorder. Atrial pulsations in the umbilical vein and retrograde diastolic blood velocity pattern in the umbilical artery were detected in every case. Group 3 was composed of 27 newborns of uncomplicated pregnancies with fetal acidemia (pH 7.10 or less) during labor. RESULTS: In groups 1-3, N-terminal peptide of proatrial natriuretic peptide concentrations were higher (P <.001) than in the control group. In group 1, neonates with abnormal umbilical artery blood velocity pattern had higher N-terminal peptide of proatrial natriuretic peptide concentrations than neonates with normal umbilical artery Doppler findings (P <.006). N-terminal peptide of proatrial natriuretic peptide concentrations were higher in group 2 (P <.002) than in groups 1 and 3. CONCLUSIONS Maternal hypertensive disorder and fetal acidemia during labor stimulate fetal atrial natriuretic peptide production, which was greatest in fetuses with severe placental insufficiency and signs of congestive heart failure.     

Middle cerebral artery Doppler indices better predictor for fetal outcome in IUGR

Objective(s)

To compare the role of middle cerebral artery and umbilical artery Doppler pulsatility indices in predicting the fetal outcome in intrauterine growth restriction.

Method(s)

The prospective study was conducted on 121 subjects. They were divided into two groups. The study group (n=71) consists of high risk group of pregnant women with growth restricted fetuses. The control group (n=50) consists of pregnant women with healthy fetuses. Both the groups were evaluated by middle cerebral artery and umbilical artery velocimetry between 28 and 41 weeks of pregnancy.

Results

Mothers with abnormal velocimetry had more number of cesarean sections to prevent fetal distress than those with normal velocimetry. The subjects with high risk factors had more number of abnormal waveforms than those without high risk factors. The predictive value of Doppler P.I for detecting abnormal fetal outcome was 94% in middle cerebral artery as against 83% for umbilical artery. The sensitivity was 71% for middle cerebral artery versus 44% for umbilical artery.

Conclusion

Growth restricted fetuses with normal flow velocimetry are at a lower risk than those with abnormal velocimetry in terms of poor Apgar score and neonatal intensive care admission. The average birth weight of the neonates with abnormal Doppler studies was lower as compared to that of neonates with normal velocimetry. Thus middle cerebral artery doppler indices were a better predictor for fetal outcome in IUGR when compared with umbilical artery in terms of sensitivity and predictive value.     

Fetal brain blood flow velocity monitoring in high risk pregnancies

OBJECTIVES: Blood velocity in the fetal vein of Galen and straight sinus is normally even and without fluctuation. Transverse sinus blood velocity pattern shows a characteristic triphasic shape. The aim of this study was to establish whether blood flow velocity pulsations in the Galen vein, straight sinus and transverse sinus velocimetry in high-risk pregnancies are related to an adverse outcome. MATERIALS AND METHODS: The Galen vein, straight sinus and transverse sinus were located by color Doppler ultrasound in 110 pregnancies complicated by pregnancy-induced hypertension and intra-uterine growth retardation with blood velocity recorded by pulsed Doppler. The incidences of blood velocity pulsations in Galen vein and straight sinus as well as peak systolic velocity, lowest diastolic velocity and resistance index (RI) from transverse sinus were correlated to pregnancy outcome, including emergency operative intervention and/or neonatal distress. Umbilical artery and venous and uterine and middle cerebral artery blood velocity was also recorded at the same time. RESULTS: Pulsating blood velocity in the Galen vein and transverse sinus was found in 40 and 10 cases, respectively. Signs of brain sparing in the middle cerebral artery were seen in 23 fetuses. Abnormal values for RI, peak systolic velocity and lowest diastolic velocity from transverse sinus were found in 20.6 and 18 cases, respectively. Galen vein pulsations were highly significantly related to adverse outcome of pregnancy and significantly more frequent in the present study than in the umbilical vein. Parameters studied in straight sinus and transverse sinus showed poor correlation with outcome of pregnancy. CONCLUSIONS: Venous pulsations in the Galen vein are significantly correlated to adverse outcome of high-risk pregnancy. Straight sinus and transverse sinus velocimetry was not associated with perinatal outcome and might not be useful in predicting fetal distress.     

Blood flow velocity waveforms of the middle cerebral artery and abnormal neurological evaluations in live-born fetuses with absent or reverse end-diastolic flow velocities of the umbilical arteries.

We studied 37 fetuses with absent or reverse end-diastolic flow velocities (AREDFV) of the umbilical arteries with respect to the mode of delivery, fetal acidosis, resistance index of the middle cerebral arteries, and abnormal neurological evaluation at the time of discharge from the department of pediatrics. A control group with normal umbilical artery flow velocity waveforms was matched for gestational age. Fetuses with AREDFV were delivered almost exclusively by cesarean section, in most cases due to fetal distress. Metabolic changes with decreased base excess values were found more often in fetuses with AREDFV, but no difference could be detected with respect to severe fetal acidosis. The number of fetuses with abnormal neurological evaluations during the first 6 months of life was significantly higher in cases with AREDFV than in the control group. More than two thirds of the fetuses with AREDFV showed an abnormal blood flow velocity waveform of the middle cerebral arteries with elevated end-diastolic flow velocities. The combination of extreme premature delivery before 28 weeks of gestation, severe idiopathic respiratory distress syndrome, and a resistance index of the middle cerebral arteries under the 5th percentile seems to be a risk factor for early neurological morbidity in fetuses with AREDFV. Premature delivery of fetuses with AREDFV--as we did during our study in order to prevent intra-uterine death or fetal asphyxia--should therefore be critically regarded in cases under 28 weeks of gestational age and abnormal flow velocity waveforms of the middle cerebral arteries.     

Pulsations of the umbilical vein: pathophysiologic aspects and fetal outcome

Continuous forward flow to the fetal heart in the umbilical vein is a normal Doppler finding. Altered fetal hemodynamics can cause a pulsatile flow pattern in the umbilical vein. Pulsations in the umbilical vein were diagnosed in 14 pregnancies complicated by fetal hydrops, cardiac malformations, arrhythmia or severe intrauterine growth retardation. To document the fetal outcome, the results were analysed retrospectively. Compared with a normal Doppler group (N = 56), a significantly higher rate of perinatal death (Alpha < 1%), (64% vs 1.75%) was diagnosed, when pulsations in the umbilical vein were present. The Apgar-score was significantly lower (4.5 vs 8.4) (p < 0.0002) in the group with pulsations in the umbilical vein. There was no significant difference of pH between the newborns of the two groups. Eight fetuses developed hydrops. Thirteen fetuses had increased reverse flow in the inferior vena cava. The vena cava of the acardiac fetus could not be identified. The knowledge of the poor outcome and the pathophysiologic relationships of fetal hemodynamics may be useful in clinical management. Therefore Doppler examination of the umbilical vein should be performed in high-risk pregnancies.     

Pulsatile umbilical venous flow and its clinical significance.

OBJECTIVE: To determine the prevalence and significance of pulsatile waveforms from the umbilical vein. SETTING: A tertiary referral clinic for high risk pregnancies. SUBJECTS: 209 fetuses from 24-41 weeks gestation. MAIN OUTCOME MEASURES: The presence of pulsatile waveforms in the umbilical vein and the pregnancy outcome. RESULTS: 9/209 fetuses demonstrated pulsatile waveforms and seven had severe growth retardation or congenital anomalies of the heart. Pulsatile flow and abnormalities of the inferior vena cava waveforms were observed in these seven but not in the two infants who were born at term. Double pulsations are described for the first time. CONCLUSION: Examination of the umbilical venous waveform for pulsatile flow is a useful test as it indicates the presence of asphyxial cardiomyopathy or congenital heart lesions.