Effect of epidural anesthesia for cesarean delivery on maternal femoral arterial and venous, uteroplacental, and umbilical blood flow velocities and waveforms

The effect of epidural anesthesia on the maternal femoral arterial and venous, uteroplacental, and umbilical circulations was studied by the pulsed Doppler technique in 13 women undergoing elective cesarean delivery. Resistance and pulsatility indices of umbilical arterial velocity waveforms did not change with the use of epidural anesthesia. In the uteroplacental circulation, these indices increased in 11 patients, suggesting an increase in resistance. Reduction of sympathetic tone in resistance and capacitance vessels was reflected in the femoral artery by an increase in systolic and end-diastolic velocities, a reversal of the post-systolic backward flow, and an increase in mean velocity. The latter also occurred in the femoral vein. The diameters of these large maternal vessels did not change. This study suggests an impairment in uteroplacental circulation associated with a drop in peripheral vascular resistance and an increase in leg blood flow after epidural anesthesia.     

Doppler sonographic findings for hypertension in pregnancy and HELLP syndrome

Doppler examinations of the umbilical artery, both uterine arteries, and the fetal middle cerebral artery were performed in the third trimester in 18 patients with pregnancy induced hypertension, 52 patients with preeclampsia, and 32 patients with HELLP syndrome and the results were correlated with the parameters fetal outcome. For 74% of the patients this was the first pregnancy, in 93% of the cases a cesarean section was necessary; 66% of the newborn babies were dystrophic and 90% of them were born prematurely. The blood flow in one uterine artery was restricted in 95% of all 102 pregnant women, only 5% did not show any pathological findings. A pathological blood flow was observed on Doppler sonography in the umbilical artery in 70% of the group and 39% showed a pathologically increased perfusion of the fetal middle cerebral artery. The average birth weights and gestational ages in the study group were markedly reduced in comparison with healthy pregnant women (pregnancy induced hypertension: 1620 g/35 weeks; preeclampsia: 1660 g/34 weeks; HELLP syndrome: 1160 g/31 weeks, respectively). The lowest values for average birth weight and gestational age occurred when all four investigated blood vessels showed pathological Doppler findings: 1180 g/31 weeks (0 to 1 pathological vascular findings: 2780 g/38 weeks; 2 pathological vascular findings: 1845 g/34.5 weeks; 3 pathological vascular findings: 1330 g/31 weeks). This Doppler study underlines the importance of examining four blood vessels: the uterine, the umbilical, and the fetal middle cerebral arteries for a complete analysis of the fetoplacental hemodynamics. On account of the severely impaired hemodynamics observed in the placentas of our patients with hypertensive diseases in pregnancy or HELLP syndrome, we believe the early diagnosis of these disorders by Doppler sonography and an early start of therapy to be essential.     

Relative abundance of placental pro-atrial natriuretic factor mRNA in normal pregnancy and pre-eclampsia

Atrial natriuretic factor (ANF), produced by cytotrophoblast cells of the human placenta, may be involved in the regulation of uteroplacental blood flow. Pre-eclampsia is associated with maternal hypertension and reduced uteroplacental perfusion. The relationship between pre-eclampsia and placental production of ANF is not known. This study measured pro-ANF mRNA levels by Northern blot analysis in placentae delivered by caesarean section at preterm and term gestations from women with normotensive and pre-eclamptic pregnancies and found no significant difference between pre-eclampsia and normal pregnancy at either gestation. This result suggests that placental production of ANF is not altered at the pretranslational level during pre-eclampsia.     

Fetal anemia,thrombocytopenia, dilated umbilical vein,and cardiomegaly due to a voluminous placental chorioangioma. A case report

We report a case of voluminous placental chorioangioma diagnosed by ultrasound and color Doppler imaging during the 20th week of pregnancy. The size of the tumor was enlarging progressively (up to 10 cm in the 32nd week), and during this time the signs of fetal intrauterine volume overload and blood cell consumption, such as cardiomegaly, umbilical vein dilation, hydramnios, anemia, and thrombocytopenia, were observed. In the 32nd week of pregnancy, the signs of uteroplacental insufficiency and fetal hypoxia appeared; therefore, the pregnancy was terminated by cesarean section, and a female infant weighing 1,870 g was delivered. She was discharged, fully recovered, after 48 days. Histopathological examination of the placental tumor showed a benign, vascular-type chorioangioma.     

Intravascular ultrasound contrast agent: an aid in imaging intervillous blood flow?

The aim of this study was to evaluate the applicability of an intravascular ultrasound contrast agent in examination of the uteroplacental circulation. Uteroplacental circulation in 25 singleton third trimester pregnancies was examined by power Doppler, first without and then with contrast agent enhancement (Levovist, Schering AG, Germany). Eight subjects had fetal growth retardation and 17 had normal-sized fetuses. The effect of the contrast agent was evaluated using computerized power Doppler signal intensity measurements. The Doppler signal intensity in the uteroplacental vessels increased within 25 sec of brachial venous injection of the contrast agent, yielding an effect which was recognizable up to 5-8 min later. There was clear enhancement of uteroplacental flow imaging after addition of the contrast agent in all of the examined pregnancies. The mean percentual intensity changes after administration of the contrast agent were 33 per cent (P<0.001) in the sub-placental myometrial area and 8 per cent (P<0.001) in the intraplacental area. No association was found between fetal growth retardation and intensity changes or absolute intensity parameters. In conclusion, intravascular ultrasound contrast agent facilitates imaging of the uteroplacental circulation. It may have a valuable role in determination of intervillous blood flow and in imaging blood perfusion in different regions of the placenta.     

Assessment of uteroplacental circulation in uncomplicated pregnancies using pulsed Doppler ultrasound

The Doppler sonography enable as a new non-invasive procedure the assessment of the uteroplacental circulation. 209 blood flow measurements (pulsed wave Doppler) were recorded between the 20th and 40th weeks of gestation from the arcuate arteries in 130 women with uncomplicated pregnancy. The S/D Ratio, the Resistance Index (RI) and the Pulsatility Index (PI) were calculated. These Indices show throughout the observation time persisting low values which reflect the optimal uteroplacental circulation in a system with low downstream impedance. We found that the S/D Ratio and the RI are appropriate parameters in the qualitative analysis of the uteroplacental perfusion. On the other side we could demonstrate that the PI depends on the maternal heart rate which explains the high variability of the values. Therefore is the PI not appropriate for the impedance measurements in uteroplacental vessels.     

The significance of uterine notching in Doppler sonography in early pregnancy as a predictor for pathologic outcome of the pregnancy

Introduction Doppler sonography of maternal vessels as a predictor for preeclampsia is an established screening method in the second trimester. Considering the first trimester its benefit has not been conclusively proven so far. Up to now the flow pattern of maternal vessels in the first trimester has only been insufficiently characterized and documented. Thus, there are only few pieces of information concerning the predictive value of the different kinds of flow patterns during the early pregnancy as regards the pathological and physiological outcome of the pregnancy. This survey aimed at evaluating the significance and the clinical importance of Doppler sonographical examinations of the Aa. uterinae during early pregnancy. It had to be analyzed whether various perfusions can be applied as a predictive value for the specific development during the pregnancy and whether therefore a risk group for pregnancy-associated hypertension can already be detected during the early pregnancy. Materials and methods A non-selected collective of 104 pregnant patients was examined with Doppler sonography and retrospectively divided into a standard collective and a high-risk collective. The standard collective contained 89 patients, who in the course of their pregnancy remained without any pathological findings. Fifteen patients, who were assigned to the high-risk collective, either developed a pregnancy-induced hypertension during their pregnancy or an intrauterine fetal growth retardation. The Doppler-sonographic examination of the Aa. uterinae was applied for the first time between the 6 and 8 weeks gestation (WG), then in the 9 WG, 10 WG, 11 WG, between the 12 and 14 WG, as well as between the 20 and 24 WG. Results Contrary to published data, there can be traced a completely transformed flow pattern in the Aa. uterinae already during the first trimester to an increasing extent. This correlates with a positive outcome of the pregnancy. There is a definite association between pathological Doppler sonography in the first third of the pregnancy and the development of a uteroplacental insufficiency as well as a pregnancy-associated hypertension (SIH) in the further course of the pregnancy. Conclusion Doppler sonography is an approved method in order to become early attentive of a reduced uterine blood flow. Applying Doppler sonographic treatment of the maternal vessels, uteroplacental insufficiency can be traced at an early stage. Pregnancies, which might develop a pregnancy-associated hypertension (SIH) or a placental insufficiency, can be detected during the early pregnancy to decrease the morbidity rate and the mortality of premature newborns. Further studies in larger collectives are necessary to obtain adequate solid datasets and to further evaluate the clinical meaning and the significance concerning pathological maternal Doppler parameters.     

Doppler ultrasound findings in therapy with urapidil

OBJECTIVE: In a prospective study we investigated, whether changes in fetal or maternal circulation can be found by Doppler sonography under therapy with urapidil. PATIENTS AND METHODS: We investigated in 11 patients with severe pregnancy-induced hypertension (PIH) or superimposed preeclampsia in the third trimester. Doppler flow results of maternal and fetal vessels before and during therapy with urapidil. Hemodynamic parameters, like maternal blood pressure, and heart rate as well as other clinical parameters were assessed. RESULTS: Whereas the antihypertensive effects in the systolic and diastolic blood pressure were significant, we couldn't find changes in the resistance indices of fetal circulation. In contrast we found a decrease in the resistance indices in maternal vessels after an average of six days of urapidil therapy. These changes were significant in the uterine artery on the side of placental insertion. CONCLUSIONS: Because of only few side effects and a safe lowering of blood pressure, therapy with urapidil seems preferable to other well known drugs. Although Doppler flow velocimetry of uteroplacental vessels has no diagnostic benefit in monitoring PIH, the findings with this method under prolonged antihypertensive therapy are a chance for a better understanding of hemodynamic changes. The decrease in the resistance indices is another argument for the use of urapidil.     

Placental expression of nitric oxide synthase during HELLP syndrome: the correlation with maternal-fetal Doppler velocimetry

BACKGROUND: To correlate Doppler waveform of the uterine and umbilical vessels to placental nitric oxide synthase (NOS) expression in pregnant women with HELLP (hemolysis, elevated liver enzymes, low platelets count) syndrome. METHODS: mRNA expression of inducible NOS (iNOS) and endothelial NOS (eNOS) was assessed, after cesarean section, in placental samples from 10 women affected by HELLP syndrome and 10 controls. Pulsatility indices on Doppler waveform analysis from uterine and umbilical arteries were measured. RESULTS: iNOS expression was significantly lower in placenta from women with HELLP syndrome than controls. When comparing the results with Doppler flow measurements, we found a negative correlation between umbilical pulsatility index and eNOS expression (r = -0.91) and a positive correlation with iNOS expression (r = 0.86). CONCLUSIONS: The reduced iNOS expression in women with HELLP syndrome may indicate the extreme placental dysfunction that is unable to compensate for the endothelial derangement and related hypertension in spite of trying to improve fetoplacental perfusion and the delivery of nutrients to the fetus.     

New score indicating placental vascular resistance

BACKGROUND: Umbilical artery Doppler velocimetry is a routine method for fetal surveillance in high-risk pregnancy. Uterine artery Doppler seems to give comparable information, but it can be difficult to interpret as there are two arteries, which might show notching and/or increased pulsatility index (PI) as signs of increased vascular impedance. Combining the information on vascular resistance on both sides in a new score might simplify and improve evaluation of placental circulation. METHODS: Uterine and umbilical artery Doppler velocimetry was evaluated in 633 high-risk pregnancies. The managing clinician was informed only about the umbilical artery flow. The umbilical artery flow spectrum was semiquantitatively divided into four blood flow classes (BFC), expressing signs of increasing vascular resistance. The uterine artery Doppler flow spectrum was divided into five uterine artery scores (UAS), taking into account presence/absence of notching and/or increase in PI. By adding UAS to BFC, a new placental score (PLS) was constructed with values ranging from 0 to 7, indicating general placental vascular resistance. The scores were related to three outcome variables: small-for-gestational age (SGA), premature delivery (<37 weeks), and cesarean section. RESULTS: All three score systems showed a significant relationship between signs of increasing vascular resistance and outcome. The new PLS showed the best association to adverse outcomes, with optimal cut-off at values exceeding score 3. CONCLUSION: Doppler velocimetry on both sides of the placenta showed a strong relationship to an adverse outcome of pregnancy. The new PLS showed a better relationship to adverse perinatal outcome than the BFC and the UAS. The PLS can simplify evaluation of uteroplacental and fetoplacental Doppler velocimetry.     

Relationship of utero- and fetoplacental blood flow velocity wave forms with pathomorphological placental findings.

Pulsed Doppler examinations were performed in 143 risk pregnancies. The resistance index (RI) values of the uteroplacental vessels and umbilical artery on the last examination before delivery were correlated to specific patterns of morphological placental findings. The sensitivity and specificity of Doppler blood flow velocity wave forms to predict placental disease as well as the significant relationships were calculated. Impaired uteroplacental perfusion is correlated with: disturbances in growth, such as reduced weight and reduced basal area (p < 0.005, p < 0.05); disturbances in villous maturation, such as prematurity or a reduction in intermediate sized villi (p < 0.05, p < 0.01), and circulation disorders, such as acute or chronic infarcts (p < 0.05), villous fibrosis (p < 0.005) or microfibrin deposits (p < 0.05). Villous immaturity was not correlated to either pathological utero- or fetoplacental blood flow. Except for acute infarcts, all these findings as well as endangiopathy of truncal arteries are also combined with high RI values in umbilical arteries (p < 0.005) possibly reflecting the 'down-stream impedance' of the fetoplacental circulation.     

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.     

Pregnancy outcomes and deliveries following laparoscopic transsection of uterine vessels: a pilot study

OBJECTIVE: To assess pregnancy outcomes and deliveries after laparoscopic uterine artery transsection (LTUV) in symptomatic women with fibroids. SETTING: Department of Obstetrics and Gynecology, Endoscopic Training Center, Baby Friendly Hospital, Kladno, Czech Republic. DESIGN: One hundred and fifty three patients underwent laparoscopic transsection of uterine vessels during a 4-year period. RESULTS: Nine of the 21 women desiring pregnancy conceived spontaneously and one after anovulation treatment. The average age of the women was 32.4 years, and the range was 26-39 years. Two women had vaginal delivery at term and one delivered vaginally at 31 weeks secondary to premature preterm rupture of membrane (PROM). Four others delivered at term by cesarean section. One woman with placenta previa was delivered by cesarean section 3 weeks before term. Mean birth weight was 3199 g (range 1710-3910 g). One spontaneous abortion was reported in the first trimester of pregnancy. One case of undesired pregnancy occurred. An extrauterine pregnancy was reported in this woman. CONCLUSION: LTUV is a minimally invasive operative procedure, that preserves the uterus and ovarian blood supply and allows for the achievement of pregnancy in women with symptomatic fibroids. Fetal growth and umbilical Doppler findings remained normal in all cases. An increased risk for preterm delivery and cesarean section was found in this small series.     

Ultrasonic assessment of abnormal umbilical cord and its circulation

Since an abnormal umbilical cord such as excessive twisting/torsion, cord compression, coiling at the fetal neck are fetal life threatening or restrict fetal growth, it is diagnosed in detail by real time B-mode ultrasound, color Doppler flow mapping, pulsed Doppler flow velocity wave form, ultrasonic fetal monitor and actocardiogram. Abnormality is evaluated by its location, size, twisting and its pitch of the cord, the grade of variable deceleration (VD), non-invasive stress CTG test in maternal movement, RI and PI, absent or reverse flow of end diastole (ARED) of umbilical arterial blood flow velocity wave form, and particularly pulsating blood flow wave of the umbilical vein related to blood stagnation in the vein and pathological vascular changes of the placental villi, fetal and neonatal blood vessels. Its treatment is maternal position change in mild cord compression, while bed rest and total tocolysis is required when the compression signs are heavy in early pregnancy. The fetus is rescued by cesarean section when threatened fetal life is indicated by signs of severe FHR change or ARED with umbilical vein flow pulsation in spite of eager conservative treatment. CNS damage of the neonate, e.g. periventricular leukomalacia (PVL) and hypoxic-ischemic encephalopathy (HIE), is inspected and treated if necessary after cesarean section.     

Complications associated with the macrosomic fetus

A retrospective study was done on 525 infants who weighed more than 4,500 g. The rates of grand multiparity, diabetes mellitus, pregnancy-induced hypertension, deliveries in women over 35 years of age, placenta previa and weight gain of more than 15 kg were higher than in a control group weighing 2,500-4,000 g. The rates of delivery with instruments and cesarean section were also significantly higher. The main indication for cesarean section in the study group was cephalopelvic disproportion, while in the control group it was repeat cesarean section. Rates of postpartum hemorrhage, shoulder dystocia, oxytocin augmentation of labor and tears in the birth canal far exceeded those in the control group. Maternal and fetal morbidity and perinatal mortality were significantly higher than in the control group. The complications were due to a difficult second stage of labor. Delivery of the macrosomic fetus by cesarean section is highly recommended except for the subgroup of women who already delivered a macrosomic child.     

Doppler flow characteristic in inferior vena cava between 22-42 weeks in intrau-terine growth restriction and normal pregnancies

Uterine blood flow restriction and placental insufficiency can cause intrauterine grow restriction. Permanent hypoxia triggers compensatory mechanisms to pro-tect vital organs. Increased placental resistance and constriction of the fetal pe-ripheral vessels, as evidenced by blood redistribution and increased right ven-tricular afterload and end-diastolic pressure lead to increased pulsality in pre-cordial veins. Doppler flow analysis of the IVC allows the indirect estimation of the fetal heart function. OBJECTIVE: The aim of the study was to compare the Doppler indices in IVC in growth restricted and normal fetuses. RESULTS: The authors found that for the normal group PVIV, PIV and S/D de-creased with advancing gestation. However in comparision in IUGR group these parameters were substantially higher. CONCLUSIONS: The improvement of maternal and fetal Doppler techniques allows us to distinguish the subgroups of IUGR fetuses with the uteroplacental insufficiency that will have an increased perinatal morbidity and mortality. Alterations in the venous blood velocity waveforms have a more precise relationship with the risk of adverse perinatal outcome than changes in the arterial blood flow usually recognized relatively early in placental function disorders.     

Doppler umbilical and uterine flow waveforms in severe pregnancy hypertension

Summary. Doppler studies of the umbilical and uteroplacental bed arterial flow velocity waveforms were performed in a series of women suffering from severe proteinuric pregnancy hypertension. Ninety-five women were studied and the mean interval between the last study and delivery was 1–4 days. An abnormally elevated umbilical artery systolic:diastolic (AB) ratio was present in 61 (64%) of the women. All 10 perinatal deaths were associated with pregnancies with an abnormal umbilical artery AB ratio. An elevated umbilical artery AB ratio was significantly associated with small-for-gestation and neonatal morbidity. Infants associated with extremely high umbilical artery AB ratios (≥ 99th centile) spent twice as long in the neonatal nursery as those with a lower value. There was no relation between the duration of hypertension and the umbilical study result. The uteroplacental bed artery flow velocity waveform did not correlate with fetal or neonatal mortality or morbidity. Patients with abnormal uteroplacental AB ratios also had abnormal umbilical artery AB ratios. We conclude that an abnormal fetal umbilical artery Doppler flow velocity waveform correlates with adverse fetal outcome in severe proteinuric pregnancy hypertension and suggest that the associated placental lesion may precede the maternal hypertension.     

Umbilical artery and uteroplacental velocimetry in pregnancies complicated by idiopathic low birthweight centile.

Umbilical artery and uteroplacental Doppler flow velocity waveforms were studied in 35 pregnancies complicated by idiopathic low birthweight centile. Thirty fetuses (86%) were below the 5th centile birthweight for gestation. Fifteen (43%) had an abnormal umbilical artery systolic to diastolic ratio. Uteroplacental waveforms were recorded in 29 of the 35 pregnancies and five (17%) showed an abnormal systolic to diastolic ratio. Abnormal uteroplacental systolic to diastolic ratios were associated with a significantly earlier gestational age at delivery and significantly more cesarean sections for fetal distress compared with normal uteroplacental systolic to diastolic ratios (p less than or equal to 0.01). The absence of umbilical artery end-diastolic frequencies was associated with a significantly earlier gestational age at delivery compared with the presence of umbilical artery end-diastolic frequencies (p less than 0.005). No differences in pregnancy outcome were observed comparing normal with abnormal amniotic fluid volume assessment. These findings suggest that Doppler studies may be useful in estimating the risk of adverse perinatal outcome for small for gestational age fetuses with no identifiable cause.     

The effect of acute and chronic antihypertensive therapy on maternal and fetoplacental Doppler velocimetry.

Maternal and feto-placental Doppler flow velocity waveforms were studied during acute and chronic antihypertensive therapy in patients with pregnancy-induced hypertension. Eight primigravidae were acutely treated with oral nicardipine. Diastolic blood pressure fell at 30, 45 and 60 min after nicardipine. The uteroplacental systolic/diastolic ratio rose significantly at 30 min, but this change was no longer apparent at 60 min. Umbilical artery and maternal brachial artery systolic/diastolic ratios were unchanged. Fifteen patients with mild pre-eclampsia were chronically treated with oral pindolol. Diastolic blood pressure fell significantly within 24 h. The uteroplacental systolic/diastolic ratio rose 3 days after pindolol. Brachial artery or umbilical artery systolic/diastolic ratios were unchanged. A control group of 15 patients with untreated mild pre-eclampsia showed a significant rise in uteroplacental and umbilical artery systolic/diastolic ratios within 7 days of starting recordings. In patients with pregnancy-induced hypertension, acute and chronic blood pressure reduction was associated with no change in umbilical artery or maternal brachial artery Doppler systolic/diastolic ratios and a transient rise in the uteroplacental systolic/diastolic ratio.