The effect of loading dose of magnesium sulfate on uterine,umbilical, and fetal middle cerebral arteries Doppler in women with severe preeclampsia: A case control study

IV MgSO₄ administration in women with severe preeclampsia resulted in a decrease in umbilical artery, uterine artery, and fetal middle cerebral artery Doppler indices.

Objective: To evaluate Doppler parameters of the umbilical artery (UmA), uterine artery (UA), and fetal middle cerebral artery (MCA) before and after MgSO₄ administration in women with severe preeclampsia. Methods: A case control study included 100 pregnant women with severe preeclampsia. Umbilical artery, uterine artery, and fetal middle cerebral artery Doppler were measured before and 20 minutes after intravenous administration of 6 g of magnesium sulfate. Results: There was a significant difference between maternal systolic blood pressure (173.20 ± 22.72 vs. 156.60 ± 19.18), diastolic blood pressure (109.60 ± 9.14 vs. 101.90 ± 10.05), and heart rate (80.52 ± 11.52 vs. 88.48 ± 12.08) before and after administration of MgSO₄ in the studied patients (p value < 0.001). There was a significant difference between umbilical artery, middle cerebral artery, and uterine artery Doppler parameters before and after administration of MgSO₄ in the studied patients (p value < 0.001). There was no significant difference between umbilical artery/middle cerebral artery with regard to RI and PI. However, there was significant difference with regard to the S/D ratio (p value < 0.001). The decrease in the values of Doppler parameters before and after administration of MgSO₄ was more in the middle cerebral artery than in the umbilical artery. Conclusion: Intravenous administration of magnesium sulfate in pregnant women with severe preeclampsia resulted in a decrease in umbilical artery, uterine artery, and fetal middle cerebral artery Doppler indices with reduced resistance to blood flow in these vessels.     

Placental Doppler velocimetry in gestational diabetes mellitus

OBJECTIVE: To evaluate if maternal glucose level and growth of the fetus were related to placental vascular impedance in pregnancy complicated by gestational diabetes mellitus. MATERIAL AND METHODS: A retrospective study of 146 gestational diabetic women of which 117 needed insulin therapy. Glycosylated hemoglobin (HbA1c) was evaluated as well as umbilical and uterine artery Doppler velocimetry. The results were related to adverse outcome of pregnancy including newborn birthweight. RESULTS: Abnormal umbilical artery blood flow velocity was seen in 5% of the cases and abnormal uterine artery flow in 16%. Uterine and umbilical artery vascular impedance was significantly lower in macrosomic newborns. There was a poor correlation between HbA1c, vascular impedance and birthweight. There were 11 cases that developed preeclampsia, all having abnormal uterine artery Doppler and two abnormal umbilical artery Doppler. CONCLUSION: Uterine and umbilical artery vascular impedance in pregnancies complicated by gestational diabetes is related to birthweight and placental weight, but not to maternal HbA1c levels. Placental Doppler ultrasound does not seem to be of clinical value for fetal surveillance in these pregnancies unless the pregnancy is complicated by preeclampsia and/or intrauterine fetal growth restriction.     

Doppler in obstetrics: beyond the umbilical artery

Doppler analysis of the umbilical and uterine arteries has long been performed in perinatal medicine to assess fetal health and maternal risk for preeclampsia. Several other vessels can be interrogated to obtain additional, vital information. Velocimetry in the fetal middle cerebral artery can yield evidence of the presence or absence of anemia and, in cases of delayed growth, of the risk of hypoxic damage. Ductus venosus waveforms are a very good indicator of impeding fetal jeopardy and should be used when umbilical artery waveforms become abnormal. Early pregnancy uterine artery Doppler reflects the status of the placental vasculature and, as such, is an excellent tool for predicting the risk of preeclampsia or intrauterine growth restriction.     

Factors Associated with Uterine Artery Doppler Anomalies in Patients with Preeclampsia

Uterine artery Doppler anomalies are associated with unfavorable outcomes in women with preeclampsia.?Objectives:?To examine the association between abnormal uterine artery Doppler and severity of preeclampsia.?Study Design:?Retrospective analysis of a population of 287 patients with preeclampsia who underwent a uterine artery Doppler velocimetric examination at the onset of preeclampsia, between 1996 and 2002. The population was classified into three groups: Group I had normal uterine artery Doppler findings; Group II had a high uterine artery resistance index; and, Group III had both high uterine artery resistance index and bilateral notches.?Results:?Compared to Group I, preeclampsia occurred earlier in Group II (76.3%) (p < 0.001), and HELLP syndrome was most frequent in Group III. The frequency of fetal growth restriction (£ 3^rd percentile) was different between groups (19.1, 32.4 and 49.7% in groups I, II and III, respectively). The perinatal death rate was significantly higher in group III than the other two groups (12.8% vs 2.9%, p < 0.01).?Conclusions:?In patients with preeclampsia, the presence of uterine artery Doppler anomalies (high resistance index with or without bilateral notches) was associated with unfavorable pregnancy outcomes.     

Fetal brain sparing is strongly related to the degree of increased placental vascular impedance

BACKGROUND: Doppler ultrasound examination has become an established method of clinical surveillance in high-risk pregnancies. Doppler indication of fetal brain sparing (BS) is an acknowledged sign of circulation redistribution during chronic hypoxia. OBJECTIVES: To evaluate the relationship between placental vascular resistance and signs of BS in middle cerebral artery (MCA) blood flow velocity. METHODS: The MCA, uterine artery, and umbilical artery (UA) were located by color Doppler ultrasound in 103 high-risk pregnancies at risk for intrauterine fetal hypoxia. The blood velocity spectrum was analyzed for the following parameters: pulsatility index (PI) and signs of notching in the uterine arteries. Z-score was calculated for the MCA PI. RESULTS: Signs of BS in the MCA were correlated to increased placental vascular impedance. The degree of BS in the MCA expressed as Z-scores was correlated to increasing vascular impedance, both in the umbilical and uterine arteries, and to adverse outcome of pregnancy. The greatest deviation in MCA PI Z-scores was seen in preterm pregnancies. CONCLUSION: A clear correlation exists between increasing placental vascular impedance and BS in the MCA. Preterm pregnancies express the greatest deviation from the mean MCA PI.     

Endothelial cell apoptosis is induced by fetal plasma from pregnancy with umbilical placental vascular disease

OBJECTIVE: Vascular disease in the umbilical placental circulation that is detected by umbilical artery Doppler study is associated with adverse fetal outcome. Endothelial cell activation and platelet consumption are features of this pathologic condition. We postulated that this was due to the local release of factors that cause endothelial cell injury and that these would spill into the fetal circulation. To test this hypothesis, we examined for the presence in fetal plasma of factors that induced endothelial cell apoptosis in pregnancies that were complicated by umbilical placental vascular disease. STUDY DESIGN: Isolated and cultured human umbilical vein endothelial cells were exposed to fetal plasma from the 3 fetal groups: normal pregnancy (n = 32 patients), pregnancy with umbilical placental vascular disease that was identified by an abnormal umbilical artery Doppler study (n = 38 patients), and pregnancy with maternal preeclampsia and normal umbilical artery Doppler study (n = 16 patients). Early apoptosis can be recognized by a loss of plasma membrane asymmetry with membrane uptake of annexin V. This was measured with annexin V and propidium iodide staining by fluorescent-activated cell scanning. Cells that underwent early apoptosis stained positive for annexin V and negative for propidium iodide (in contrast with cells that underwent necrosis). Cytosolic proteolytic activity was also measured. The lysates from endothelial cells that were stimulated by fetal plasma from umbilical placental vascular disease were tested for caspase-3 and caspase-8 activities by a fluorescent assay with spectrofluorophotometry. RESULTS: The percentage of endothelial cells that underwent apoptosis was significantly higher (P <.05) when stimulated with fetal plasma from pregnancies with umbilical placental vascular disease (17.71% +/- 1.31%) than with fetal plasma from normal pregnancies (9.76% +/- 0.87%). In the presence of maternal preeclampsia with normal umbilical artery Doppler study, the percent of apoptotic cells (11.31% +/- 1.59%) was similar to that of the normal group. In the group with abnormal umbilical artery Doppler study, there was no difference between pregnancies with preeclampsia (n = 17 pregnancies) and without preeclampsia (n = 21 pregnancies). The protease activity of caspase-3 was significantly enhanced in the group with umbilical placental vascular disease compared with normal pregnancy (0.79 +/- 0.06 vs 0.45 +/- 0.08 microMol/L). However, no difference in caspase-8 activity was detected (0.66 +/- 0.05 vs 0.56 +/- 0.05 microMol/L). CONCLUSION: Endothelial cell apoptosis is a feature of umbilical placental vascular disease. Our study demonstrates the presence of factors in the fetal plasma that caused endothelial cells to undergo early apoptosis. This increased apoptosis was only seen in the presence of placental vascular disease and was independent of the presence or absence of maternal preeclampsia. Our results indicate that programmed endothelial cell death occurs in the fetal circulation as a part of the injury that is associated with the development of umbilical placental vascular disease. The caspase-3, rather than caspase-8, signal transduction pathway appears to be involved in the mediation of endothelial cell apoptosis that was detected in our study.     

Correlation of Doppler velocimetry findings in twin pregnancies including course of pregnancy and fetal outcome

OBJECTIVE: Subject of the study was the significance of umbilical artery Doppler velocimetry findings for the further course of pregnancy and fetal outcome in cases of twin pregnancies. METHODS: In 206 cases of twin pregnancy, the umbilical artery was examined using Doppler velocimetry in the median 9 days prior to delivery, and the result was correlated with the further course of pregnancy and fetal outcome. 174 pregnancies showed normal Doppler findings of the umbilical artery (group A), 32 twin pregnancies showed pathological Doppler findings of at least one twin (group B). The median of the maternal age and the parity between the groups were not different. RESULTS: In group B (pathological Doppler findings), intrauterine growth retardation and pre-eclampsia occurred 5 times more often than in group A (normal Doppler findings). The total rate of cesarean sections was not different between the study populations; the rate of deliveries by cesarean section in group B was significantly increased by a factor of 2.4 due to a pathological CTG. The median birth weight and the gestational age at birth were significantly lower in group B (1,660 g; 35 weeks) as compared to group A (2,460 g; 37 weeks; p<0.001). In group B, the rate of premature deliveries up to reaching the 34th week of gestation was 3. 4 times higher; the rate of SGA newborns was 6.3 times higher. Perinatal mortality was increased by a factor of 1.5 in group B compared to group A. CONCLUSION: The Doppler velocimetry findings have considerable effects on the further course of a multiple pregnancy. In case of pathological Doppler findings, early hospitalization and close monitoring of the pregnancy should be performed. In cases of additional pathological findings (maternal illness, pathological Doppler findings of fetal blood vessels), termination of the pregnancy has to be considered.     

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.     

The effect of methyldopa treatment on uterine,umblical and fetal middle cerebral artery blood flows in preeclamptic patients

The purpose of this study was to evaluate the efficacy of methyldopa in the treatment of preeclamptic patients. This study was performed on 24 preeclamptic women who were in between 25–36 weeks of gestational age. 24 healthy pregnant women were taken as control group. Before starting treatment, 24 preeclamptic patients were examined with Doppler ultrasound. Pulsatility index, resistance index, systolic/diastolic ratio of uterine, umblical and fetal middle cerebral arteries were measured. Preeclamptic patients were treated with totally 1 g methyldopa per day. After 7 d, patients were reexamined with Doppler ultrasound. The effect of methyldopa on uterine, umblical and fetal middle cerebral artery blood flows were detected. Only one control with Doppler ultrasound was done to the healthy pregnant women. Before methyldopa treatment to the preeclamptic women, pulsatility index (PI), resistance index (RI) and systolic/diastolic ratio (S/D) on uterine and umblical arteries were significantly higher than the control group. However, fetal middle cerebral artery (MCA) values were significantly lower than the control group. When Doppler results of preeclamptic patients before and after the methyldopa treatment were compared, no significant differences in terms of Pulsatility Index, Resistance IndexI and S/D ratio of umblical and fetal middle cerebral arteries were found. However, the results of uterine artery were significantly lower after the treatment in preeclamptic patients. Treatment with methyldopa lowered the uterine artery resistance in preeclamptic patients but did not effect the resistance of umblical and fetal middle cerebral artery. Received: 27 March 2001 / Accepted: 5 June 2001     

静脉导管、脐静脉和脐动脉及大脑中动脉血流检测对子痫前期胎儿预后分析

目的:探讨子痫前期(PE)胎儿静脉导管(DV)、脐静脉(UV)和脐动脉(UA)及大脑中动脉(MCA)血流检测对围生儿预后分析。方法:应用彩色多普勒超声检测PE胎儿的DV、UV和UA及MCA血流参数,并与相应孕周正常妊娠胎儿的血流测值进行对照分析,研究分析其与胎儿不良结局的关系。结果:28~31+6周及36周~分娩前,重度PE胎儿的DV、UV血流测值较正常、轻度PE胎儿升高(P0.05),轻度PE与正常胎儿比较差异无统计学意义(P0.05)。32周~35+6周,PE胎儿的DV血流参数测值PLI、PVIV、PIV及Qdv/Quv随着PE严重程度呈上升趋势(P0.05)。28周~分娩前,重度PE胎儿UA血流测值较正常、轻度PE胎儿升高(P0.05),轻度PE胎儿UA血流测值RI、PI、S/D与正常胎儿比较差异无统计学意义(P0.05),28~36周PE胎儿的MCA血流测值RI、PI、S/D与正常胎儿比较差异有统计学意义(P0.05)。PE胎儿DV、UV、UA血流测值与新生儿的出生体重、Apgar评分、脐动脉血氧饱和度、脐静脉p H值呈负相关。PE胎儿DV的PVIV、PIV,UV的Qdv/Quv,UA的PI、S/D和MCA的RI值与新生儿出生结局相关(P0.05)。结论:DV、UV血流频谱变化可反映PE胎儿宫内状况及预测出生不良结局,若结合UA、MCA血流频谱进行联合分析,将能更准确地评估胎儿的宫内状况。     

The maternal plasma soluble vascular endothelial growth factor receptor-1 concentration is elevated in SGA and the magnitude of the increase relates to Doppler abnormalities in the maternal and fetal circulation.

OBJECTIVES: The soluble form of vascular endothelial growth factor receptor-1 (sVEGFR-1), an antagonist to vascular endothelial growth factor and placental growth factor, has been implicated in the pathophysiology of preeclampsia. Preeclampsia and pregnancy complicated with small for gestational age (SGA) fetuses share some pathophysiologic derangements, such as failure of physiologic transformation of the spiral arteries, endothelial cell dysfunction, and leukocyte activation. The objectives of this study were to: (1) determine whether plasma concentrations of sVEGFR-1 in mothers with SGA fetuses without preeclampsia at the time of diagnosis are different from those in patients with preeclampsia or normal pregnant women, and (2) examine the relationship between plasma concentrations of sVEGFR-1 and Doppler velocimetry in uterine and umbilical arteries in patients with preeclampsia and those with SGA. STUDY DESIGN: A cross-sectional study was conducted to determine the concentrations of the soluble form of VEGFR-1 in plasma obtained from normal pregnant women (n = 135), women with SGA fetuses (n = 53), and patients with preeclampsia (n = 112). Patients with SGA fetuses and those with preeclampsia were sub-classified according to the results of uterine and umbilical artery Doppler velocimetry examinations. Plasma concentrations of sVEGFR-1 were determined by an ELISA. Since these concentrations change with gestational age, differences among various subgroups were statistically estimated with the delta value, defined as the difference between the observed and expected plasma sVEGFR-1 concentration. The expected values were derived from regression analysis of plasma sVEGFR-1 concentrations in normal pregnancy. Regression analysis and univariate and multivariate analysis were employed. RESULTS: (1) Mothers with SGA fetuses had a mean plasma concentration of sVEGFR-1 higher than normal pregnant women (p < 0.001), but lower than patients with preeclampsia (p < 0.001). (2) Among patients with SGA fetuses, only those with abnormal uterine artery Doppler velocimetry had a mean plasma sVEGFR-1 concentration significantly higher than normal pregnant women (p < 0.001). (3) Among mothers with SGA fetuses in whom Doppler velocimetry was performed (n = 41), those with abnormalities in both the uterine and umbilical artery velocimetry had the highest mean delta of sVEGFR-1 plasma concentration (mean +/- standard deviation (SD): 0.69 +/- 0.29). Conversely, patients who had normal Doppler velocimetry in both uterine and umbilical arteries had the lowest mean delta (mean +/- SD: 0.09 +/- 0.29) of sVEGFR-1 plasma concentrations (ANOVA; p < 0.001). (4) Among patients with preeclampsia in whom Doppler velocimetry was performed (n = 69), those with abnormalities in both the uterine and umbilical artery velocimetry had the highest mean delta sVEGFR-1 plasma concentration (mean +/- SD: 1.01 +/- 0.22) among all groups classified (ANOVA; p < 0.001). (5) Among patients with SGA and those with preeclampsia, there was a relationship (Chi-square for trend p < 0.001 for both) between the severity of Doppler velocimetry abnormalities and the proportion of patients who had high delta sVEGFR-1 plasma concentrations (defined as a concentration two standard deviations (2SD) above the mean delta of normal pregnant women). (6) Multiple regression analysis suggested that the diagnostic category (e.g., SGA or preeclampsia), Doppler abnormalities, and gestational age at blood sampling were associated with an increase in plasma sVEGFR-1 concentrations (p < 0.001). CONCLUSIONS: These observations provide support for the participation of the soluble receptor of vascular endothelial growth factor in the pathophysiology of SGA with abnormal uterine artery Doppler velocimetry and preeclampsia. An excess of sVEGFR-1 is released into the maternal circulation of patients with preeclampsia and those with SGA fetuses, as abnormalities of impedance to blood flow involve uterine and umbilical circulation.     

Assessment of nitrite oxide and maternal–fetal Doppler parameters during pregnancy

Objective: The objective was to evaluate and compare the whole blood nitrite concentration in the three trimesters of pregnancy. Additionally, we investigate whether there is any relation between nitrite concentrations and Doppler ultrasound analysis of some maternal and fetal vessels.

Methods: Thirty-three healthy pregnant women were examined at the first (11–14 weeks), second (20–24 weeks) and third trimester (34–36 weeks) of pregnancy. In the three exams, we determined the maternal whole blood nitrite concentration and uterine arteries Doppler analysis to determine pulsatility index (PI), and resistance index (RI). In the second and third trimester we also performed fetal umbilical and middle cerebral arteries PI and RI. We compared the concentrations of nitrite in three trimesters and correlated with Doppler parameters.

Results: No difference was observed in the whole blood nitrite concentrations across trimesters: 151.70?±?77.90?nmol/ml, 142.10?±?73.50?nmol/ml and 147.10?±?87.30?nmol/ml; first, second and third trimesters, respectively. We found no difference in correlation between whole blood nitrite concentration and Doppler parameters from the evaluated vessels.

Conclusions: In healthy pregnant women, the nitrite concentrations did not change across gestational trimesters and there was also no strong correlation with Doppler impedance indices from maternal uterine arteries and fetal umbilical and middle cerebral arteries.     

Doppler examinations of fetal and uteroplacental blood flow in AGA and IUGR fetuses before and after maternal physical exercise with the bicycle ergometer

OBJECTIVE: To study changes in uteroplacental and fetal circulation after maternal exercise in appropriate-for-gestational-age fetuses (AGA) and intrauterine-growth-retarded fetuses (IUGR). MATERIALS AND METHOD: 33 women with an uncomplicated course of pregnancy and ten women with IUGR were examined. Physical stress was caused through a bicycle ergometer with 1.25 W/kg maternal weight. Doppler examinations were performed in the umbilical artery, fetal aorta, middle cerebral and in the uterine artery. Fetal heart rate was documented by monitoring. Maternal lactate and glucose levels as well as maternal blood pressure and heart rate were recorded. RESULTS: No significant changes after cycling could be observed in umbilical and uterine vessels either in the normal pregnancies or in pregnancies with IUGR. In contrast, in the fetal aorta an increase of the RI was recorded in both groups (an increase of 16% [P<0.01] and 18% [P<0.05], respectively for AGA and IUGR cases). In cerebral arteries a decrease of the RI was observed after cycling in both groups (a decrease of 24% [P<0.01] and 13% [P<0.05], respectively for AGA and IUGR cases). In AGA fetuses the RI of the aorta and middle cerebral artery returned to pre-test level by the 18th minute of examination. In IUGR fetuses the RI of the aorta and middle cerebral artery did not return to pre-test levels at the end of the test. Fetal heart rate remained unchanged in both groups. Maternal blood pressure and heart rate increased during the exertion phase but returned to initial values at the end of the test. A 21% and 24% (for AGA and IUGR groups respectively) reduction of maternal glucose values after exercise was observed (P<0.001). Lactate values doubled in both groups after exercise (P<0.001). CONCLUSION: From the results obtained we conclude that maternal exercise does not significantly alter uterine and umbilical perfusion in AGA and IUGR pregnancies, suggesting an absence of change in the uterine vascular bed resistance. However, submaximal maternal exercise was followed by fetal cerebral vasodilatation and an increase of resistance in the fetal aorta that was more evident in IUGR fetuses. This might be due to slight fetal hemoglobin desaturation in those cases.     

Effect of short-term maternal fasting in the third trimester on uterine, umbilical, and fetal middle cerebral artery Doppler indices

Objective

To assess the effect of short-term maternal fasting on uterine, umbilical, and middle cerebral artery Doppler indices, and on maternal serum glucose levels and fetal behavior.

Methods

Maternal serum glucose levels, fetal biophysical profiles, and uterine, umbilical, and middle cerebral artery Doppler indices were assessed in 110 healthy women in the third trimester of pregnancy after fasting for 10-12 hours and 2 hours after a balanced meal.

Results

Maternal serum glucose levels, nonstress test results, fetal breathing movements, and biophysical profile improved after a meal compared with after fasting for 10-12 hours. Uterine, umbilical, and middle cerebral artery Doppler indices were not significantly different after fasting and after a meal.

Conclusion

Short-term maternal fasting during the third trimester of pregnancy has no effect on uterine, umbilical, or fetal cerebral artery Doppler indices, and has a transient but significant effect on maternal serum glucose levels and fetal behavior.     

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 implications of Doppler ultrasound analysis of the uterine and umbilical arteries

Serial Doppler velocimetry of the umbilical and uterine arteries has revealed a relatively clear separation between normal and abnormal waveforms. Abnormal umbilical artery waveforms are defined by a systolic/diastolic ratio greater than or equal to 3 in the last 10 weeks of pregnancy. When abnormal waveforms persist, fetal growth retardation and adverse perinatal outcome are likely. Abnormal uterine artery waveforms are also recognized by a systolic/diastolic ratio averaged from both vessels of more than 2.6 after 26 weeks. In addition, the abnormal vessel will usually contain a persistent diastolic notching. Abnormal uterine vessels strongly correlate with the presence or subsequent development of preeclampsia and fetal growth retardation. Doppler velocity flow provides valuable insights into the pathophysiology of various disease states. It provides a basis for new clinical and basic research into disease mechanisms and methods for improving perinatal and maternal morbidity.     

Preeclampsia--abnormal uterine artery Doppler is related to recurrence of symptoms during the next pregnancy

BACKGROUND: Impaired trophoblast invasion is suggested as the main cause of reduced placental perfusion, which results in fetal growth restriction and preeclampsia. Immunological response against the invading tissue has been given as the explanation. Preeclampsia frequently recurs during the next pregnancy. Doppler ultrasound can predict increased vascular impedance in the uteroplacental circulation. Whether signs of increased vascular resistance in pregnancies complicated by preeclampsia are predictive of recurrence during the next pregnancy is unknown. METHODS AND MATERIAL: Uterine artery Doppler was performed in 570 pregnant women with preeclampsia. Of these, 139 became pregnant again. The uterine artery Doppler results during the first pregnancy were related to symptoms of preeclampsia in the succeeding pregnancy. RESULTS: Preeclampsia developed again in 43 of the 139 women. Pregnancies with signs of increased uterine artery vascular impedance during the first pregnancy were 3.4 times more likely to develop preeclampsia again (CI 1.58-7.6). Similar results for a small for gestational age newborn were 9.7 (CI 1.1-90). CONCLUSION: Increased uterine artery vascular impedance in pregnancies complicated by preeclampsia increases the likelihood of recurrence and growth restriction during the next pregnancy. The Doppler information gathered during the first pregnancy might thus select cases for special surveillance and possibly prophylactic anti-platelet treatment in the next pregnancy.     

Interaction between risk factors for fetal growth retardation associated with abnormal umbilical artery Doppler studies

BACKGROUND: The role of antenatal risk factors associated with the occurrence of fetal growth restriction complicated by abnormal umbilical artery Doppler studies has not yet been studied extensively. We evaluated the role and the interactions of antenatal antecedents of fetal growth restriction complicated by abnormal umbilical artery end-diastolic velocities. METHODS: We compared antenatal variables in 183 pregnancies complicated by fetal growth retardation and abnormal umbilical artery Doppler studies and 549 appropriately grown fetuses with normal end-diastolic velocity waveform in the umbilical artery. Logistic regression was used to evaluate the association between antenatal variables and fetal growth retardation and to test for interaction. RESULTS: In logistic models, increasing maternal age [odds ratio (OR) 1.06, 95% confidence interval (CI) 1.01-1.11], nulliparity (OR 2.2, 95% CI 1.37-3.5), smoking during pregnancy (OR 2.56, 95% CI 1.56-4.22), preeclampsia (OR 27.5, 95% CI 15.1-49.9), first-trimester hemorrhage (OR 2.25, 95% CI 1.32-3.82) and low (< 0.2 kg/week) weight gain in pregnancy (OR 3.48, 95% CI 1.71-3.05) were significantly associated with an increased risk of fetal growth restriction complicated by abnormal Doppler studies. These risk factors were also significantly correlated with the occurrence of absent/reversed end-diastolic blood flow in the umbilical artery. Maternal smoking during pregnancy interacted negatively with preeclampsia but positively with a low weight gain in pregnancy. CONCLUSIONS: The results of this study have shown that antenatal risk factors for intrauterine growth retardation (IUGR) complicated by abnormal Doppler studies are similar to those associated with the birth of a small-for-gestational-age infant. Preeclampsia, maternal smoking and low weight gain in pregnancy play a significant causal role in the origin of fetal growth restriction associated with abnormal uteroplacental blood flow.     

The effects of epidural anesthesia on the Doppler velocimetry of umbilical and uterine arteries in normal and hypertensive patients during active term labor

To study the effects of epidural anesthesia on uterine and umbilical artery blood flow in preeclampsia, we observed 25 patients in active labor at 36 or more weeks' gestation. Seven had preeclampsia, eight had chronic hypertension, and ten had no complications. Doppler velocimetry of the uterine and umbilical arteries was performed before and after intravenous fluid loading and at 30 and 60 minutes after epidural blockade. Maternal vital signs and fetal heart rate were monitored continuously. After epidural block, mean maternal blood pressure fell significantly in all groups, but no maternal hypotension was observed. Mean maternal and fetal heart rates were unchanged. After epidural block, mean uterine artery systolic-diastolic (S-D) ratios did not change in the chronic-hypertension and normal groups, but fell significantly in the preeclamptic group to values similar to those of the normal group. Umbilical artery S-D ratios did not change in any group. In preeclamptic pregnancy, epidural anesthesia may help to reduce uterine artery vasospasm and may benefit intrapartum fetal well-being.