Abnormal Flow Velocity Waveforms Research Articles

Impact of different prenatal management strategies in short‐ and long‐term outcomes in monochorionic twin pregnancies with selective intrauterine growth restriction and abnormal flow velocity waveforms in the umbilical artery Doppler: a retrospective observational study of 108 cases

To review perinatal and neurodevelopmental outcome (NDO) following selective fetoscopic laser coagulation (SFLC), cord coagulation (CC) or expectant management of monochorionic diamniotic twin pregnancies complicated with selective intrauterine growth restriction (sIUGR) and absent or reverse end-diastolic flow (AREDF) in the umbilical arteries (UA). Single-centre retrospective observational study. 108 cases of sIUGR diagnosed before 26+6 weeks' gestation with AREDF in the UA. Survival rate and potential risk factors were analysed. NDO was assessed using parental questionnaires. Survival, gestational age at delivery and NDO. SFLC, CC and EM were performed in 13, 50 and 45 cases, respectively, with an overall survival of 23.1, 40 and 77.8% and intrauterine demise of the co-twin of 30.8, 10 and 6.7% respectively. Intrauterine demise of the sIUGR twin occurred in 76.9 and 17.8% following SFLC and EM, respectively. The discordance in EFW at diagnosis was higher and absent/negative a-wave in the ductus venosus (DV) was more prevalent in the surgical groups. NDO in survivors at follow up was abnormal in 0 and 18% in the smaller twin following SFLC and EM, respectively, and in 25, 24 and 21% in the larger twin following SFLC, CC and EM, respectively. SFLC yielded a poor result. EM seems a valid option when EFW discordance is <30% and a-wave in DV is positive. Otherwise, CC should be considered to protect the AGA co-twin. The long-term outcome of both small and large twins seems unaffected by the choice in primary prenatal management strategy. In type II sIUGR in MC twins, long-term neurodevelopment is normal in over 80% of the survivors.

Higroma quístico retronucal como marcador de anomalías cromosómicas en el primer trimestre de la gestación

Antecedentes. El higroma quístico retronucal es el marcador de anomalías cromosómicas identificado con mayor frecuencia en el tamizaje del primer trimestre. Objetivo. Evaluar la asociación del higroma quístico retronucal y anomalías cromosómicas diagnosticadas con el cariotipo, entre el primer y segundo trimestre del embarazo. Diseño. Estudio retrospectivo. Institución. Instituto Latinoamericano de Salud Reproductiva (ILSAR), Lima, Perú. Pacientes. Fetos con higroma quístico retronucal. Método. Estudio de fetos con higroma quístico retronucal, obtenidos de la base de datos de ILSAR, entre agosto del 2007 y mayo del 2018, diagnosticados por ecografía entre las 11 y 13,6 semanas. El higroma quístico retronucal se definió como la presencia de contenido líquido tabicado en el corte axial retronucal con un grosor mayor al percentil 95 del valor de translucencia nucal aumentada para la longitud corona-nalga. Se obtuvo el cariotipo entre el primer y segundo trimestre en material obtenido por biopsia de vellosidades coriales (BVC) o amniocentesis (AMC). Principales medidas de resultados. Los resultados del cariotipo fueron comparados entre los casos de higroma quístico solo y los casos que tuvieron higroma y adicionalmente otro marcador. Resultados. De un total de 459 procedimientos invasivos realizados en fetos con alto riesgo para anomalías cromosómicas en base al Fetal test de España, hubieron 162 casos de anomalías cromosómicas (35,3%) y se identificó 104 casos de higroma quístico retronucal (22s7%). El hallazgo de higroma quístico retronucal se asoció con mayor presencia de anomalías cromosómicas, comparado con los fetos sin higroma quístico (52,9% vs. 30,1%; p&lt;0,001). De 61 casos de higroma solo, 42,3% tenían anomalía cromosómica, y cuando el higroma estaba asociado a otros marcadores (hidrops fetal, ductus venoso anormal, cardiopatía, ausencia de hueso nasal), hubo 65,1% de anomalías cromosómicas. Hubo diferencia estadística significativa (p=0,003) para la presencia de monosomía X, entre el grupo con higroma solo y el de higroma + hidrops fetal. No hubo diferencia en el grosor del higroma entre el grupo con y sin anomalía cromosómica. Conclusiones. El higroma quístico retronucal es un marcador de riesgo con alto valor predictivo para anomalías cromosómicas. Su identificación en el tamizaje prenatal podría ser indicación para recomendar una prueba diagnóstica. Cuando se asocia a anormalidad del flujo del ductus venoso o hidrops fetal, aumentan significativamente las anomalías cromosómicas. El higroma asociado conhidrops se vinculó mayoritariamente a la monosomía X, mientras que el higroma asociado con onda de velocidad de flujo-OVF de ductus venoso anormal a la trisomía 21.

Cardiac defects, nuchal edema and abnormal lymphatic development are not associated with morphological changes in the ductus venosus

BackgroundIn human fetuses with cardiac defects and increased nuchal translucency, abnormal ductus venosus flow velocity waveforms are observed. It is unknown whether abnormal ductus venosus flow velocity waveforms in fetuses with increased nuchal translucency are a reflection of altered cardiac function or are caused by local morphological alterations in the ductus venosus. AimThe aim of this study was to investigate if the observed increased nuchal translucency, cardiac defects and abnormal lymphatic development in the examined mouse models are associated with local changes in ductus venosus morphology. Study designMouse embryos with anomalous lymphatic development and nuchal edema (Ccbe1−/− embryos), mouse embryos with cardiac defects and nuchal edema (Fkbp12−/−, Tbx1−/−, Chd7fl/fl;Mesp1Cre, Jarid2−/−NE+ embryos) and mouse embryos with cardiac defects without nuchal edema (Tbx2−/−, Fgf10−/−, Jarid2−/−NE− embryos) were examined. Embryos were analyzed from embryonic day (E) 11.5 to 15.5 using markers for endothelium, smooth muscle actin, nerve tissue and elastic fibers. ResultsAll mutant and wild-type mouse embryos showed similar, positive endothelial and smooth muscle cell expression in the ductus venosus at E11.5–15.5. Nerve marker and elastic fiber expression were not identified in the ductus venosus in all investigated mutant and wild-type embryos. Local morphology and expression of the used markers were similar in the ductus venosus in all examined mutant and wild-type embryos. ConclusionsCardiac defects, nuchal edema and abnormal lymphatic development are not associated with morphological changes in the ductus venosus. Ductus venosus flow velocity waveforms most probably reflect intracardiac pressure.

Absence of an anatomical origin for altered ductus venosus flow velocity waveforms in first‐trimester human fetuses with increased nuchal translucency

To perform a morphological evaluation of the ductus venosus, heart and jugular lymphatic sac (JLS) in first-trimester human fetuses with normal and abnormal ductus venosus flow velocity waveforms (DV-FVWs) and normal and increased nuchal translucency (NT). Postmortem examination was performed on fetuses with increased NT or structural malformations with previous NT and DV-FVW measurements. Ductus venosus morphology was examined using markers for endothelium, smooth muscle actin (SMA), nerves and elastic fibers. Fetal hearts were studied by microscopy. The nuchal region was analyzed using markers for lymphatic vessels, endothelium, SMA and nerves. Two trisomy 21 and two trisomy 18 fetuses with increased NT and abnormal DV-FVWs were analyzed. As a control, one euploid anencephalic fetus with normal NT, cardiac anatomy and DV-FVWs was examined. Similar endothelial and SMA expression was observed in the ductus venosus in all fetuses. Nerve and elastic fiber expression were not detected. Three trisomic fetuses showed cardiac defects, one trisomic fetus demonstrated normal cardiac anatomy. The JLS was abnormally enlarged or contained red blood cells in all trisomic fetuses. The control fetus showed a normal JLS. Abnormal DV-FVWs are not justified by alterations in ductus venosus morphology. DV-FVWs most probably reflect intracardiac pressure. © 2016 John Wiley & Sons, Ltd.

Doppler abnormalities in monochorionic diamniotic twin pregnancies with discordant growth.

We studied whether abnormal umbilical artery (UA) Doppler flow velocity waveforms occur with higher frequency in monochorionic diamniotic (MCDA) twin gestations with discordant fetal growth and whether this impacted neonatal outcome. We performed a retrospective study of MCDA twin pairs. We collected data from an electronic medical record. We classified pregnancies as discordant if there was at least 20% birth weight discordance. Abnormal UA Doppler velocity waveforms included absent or reversed end diastolic flow. We analyzed the data with chi square, Student's t-test and analysis of variance as appropriate. Seventy-three twin pairs met criteria for inclusion, including 16 with discordant growth. The discordant group was significantly more affected with twin-to-twin transfusion syndrome (TTTS) (P=0.02). The smaller fetuses in discordant pairs were more likely to display abnormal UA Doppler flow velocity waveforms (P<0.01). These neonates also had lower Apgar scores (P=0.03) and were more likely to require care in a neonatal intensive care unit. Our findings persisted after excluding pregnancies with TTTS. In MCDA twin gestations complicated by discordant growth, there is an increased frequency of abnormal UA Doppler flow velocity waveforms in small fetuses, and these neonates face clinical challenges after birth.

First‐trimester uterine artery Doppler and adverse pregnancy outcome: a meta‐analysis involving 55 974 women

To determine the accuracy with which uterine artery Doppler in the first trimester of pregnancy predicts pre-eclampsia and fetal growth restriction, particularly early-onset disease. We searched MEDLINE (1951-2012), EMBASE (1980-2012) and the Cochrane Library (2012) for relevant citations without language restrictions. Two reviewers independently selected studies that evaluated the accuracy of first-trimester uterine artery Doppler to predict adverse pregnancy outcome and performed data extraction to construct 2 × 2 tables. We synthesized sensitivity and specificity for various Doppler indices using a bivariate random-effects model. From 1866 citations, we identified 18 studies (55,974 women). The sensitivity and specificity of abnormal uterine artery flow velocity waveform (FVW) in the prediction of early-onset pre-eclampsia were 47.8% (95% CI: 39.0-56.8) and 92.1% (95% CI: 88.6-94.6), and in the prediction of early-onset fetal growth restriction were 39.2% (95% CI: 26.3-53.8) and 93.1% (95% CI: 90.6-95.0), respectively. The sensitivities for predicting any pre-eclampsia and fetal growth restriction were 26.4% (95% CI: 22.5-30.8) and 15.4% (95% CI: 12.4-18.9), respectively, and the specificities were 93.4% (95% CI: 90.4-95.5%) and 93.3% (95% CI: 90.9-95.1), respectively. The number needed to treat (NNT) with aspirin to prevent one case of early-onset pre-eclampsia fell from 1000 to 173 and from 2500 to 421 for background risks varying between 1% and 0.4%, respectively. First-trimester uterine artery Doppler is a useful tool for predicting early-onset pre-eclampsia, as well as other adverse pregnancy outcomes. Based on the NNT, abnormal uterine artery Doppler in low-risk women achieves a sufficiently high performance to justify aspirin prophylaxis in those who test positive.

Doppler ultrasound in pregnancies with hypertension.

Doppler studies of the arcuate and umbilical arteries were performed longitudinally commencing at 24 weeks or less, in 29 pregnant women with chronic hypertension. The hypothesis was that pregnant women with chronic hypertension who develop superimposed gestational proteinuric hypertension and/or deliver small for gestational age babies are those who have abnormal arcuate and/or umbilical flow velocity waveforms. Abnormal arcuate waveforms occurred in 7 women and abnormal umbilical waveforms in 12. Nine babies were small for gestational age, and 6 of them had abnormal arcuate waveforms. Abnormal arcuate waveforms were significantly associated with the delivery of a small for gestational age baby (p = .001) and identified those babies where early delivery was necessary for fetal reasons. All small for gestational age babies had abnormal umbilical waveforms. Superadded gestational proteinuria (or preeclampsia) occurred in 8 pregnancies, however, only 3 had abnormal arcuate waveforms. An abnormal arcuate waveform did not predict the later development of gestational proteinuria. An abnormal umbilical waveform however, was associated with the subsequent development of gestational proteinuria. We consider that these findings need to be confirmed in a larger study.

Abnormal arterial flows by a distributed model of the fetal circulation

Modeling the propagation of blood pressure and flow along the fetoplacental arterial tree may improve interpretation of abnormal flow velocity waveforms in fetuses. The current models, however, either do not include a wide range of gestational ages or do not account for variation in anatomical, vascular, or rheological parameters. We developed a mathematical model of the pulsating fetoumbilical arterial circulation using Womersley's oscillatory flow theory and viscoelastic arterial wall properties. Arterial flow waves are calculated at different arterial locations from which the pulsatility index (PI) can be determined. We varied blood viscosity, placental and brain resistances, placental compliance, heart rate, stiffness of the arterial wall, and length of the umbilical arteries. The PI increases in the umbilical artery and decreases in the cerebral arteries, as a result of increasing placental resistance or decreasing brain resistance. Both changes in resistance decrease the flow through the placenta. An increased arterial stiffness increases the PIs in the entire fetoplacental circulation. Blood viscosity and peripheral bed compliance have limited influence on the flow profiles. Bradycardia and tachycardia increase and decrease the PI in all arteries, respectively. Umbilical arterial length has limited influence on the PI but affects the mean arterial pressure at the placental cord insertion. The model may improve the interpretation of arterial flow pulsations and thus may advance both the understanding of pathophysiological processes and clinical management.

Fetal Intracranial Hemorrhage (Fetal Stroke): Report of Four Antenatally Diagnosed Casesand Review of the Literature

Neonatal intracranial hemorrhage (ICH) has been estimated to be high in premature infants, occurring in approximately 40% of infants of less than 32 weeks' gestation. However, the true incidence of ICH in utero has not been determined. We present our experience with four cases of fetal ICH (fetal stroke), which was detected prenatally by ultrasonography (US). Four cases of fetal ICH were identified over a 2-year period at the prenatal unit of Taichung Veterans General Hospital, Taiwan. Prenatal and neonatal sonograms, computed tomography (CT) scan or magnetic resonance imaging (MRI), medical records, and the clinical course were assessed retrospectively. In each case, a series of initial and follow-up obstetric sonograms were available. Fetal stroke was recognized by several sonographic features: irregular echogenic brain mass, intraventricular echogenic foci or periventricular echodensities; ventriculomegaly; and posthemorrhagic hydrocephalus (PHH). A detailed investigation for possible etiology of fetal ICH was performed in all cases. Transabdominal US showed hyperechoic lesions in the lateral ventricle and ventriculomegaly in three of the four fetuses, and a massive intraparenchymal hemorrhage in the remaining one. Three fetuses were born vaginally and one by cesarean section due to an enlarged head circumference. Abnormal nonstress tests and abnormal flow velocity waveforms in the umbilical and middle cerebral arteries were present in two cases. Intrapartum fetal death and neonatal death occurred in the first two cases associated with maternal preeclampsia at 31 and 27 weeks, respectively. In the remaining two infants, the one in case 3 underwent ventriculoperitoneal shunting, which developed normally at the age of 18 months. The other infant in case 4 had PHH after suspicious choroids plexus hemorrhage, and the detailed information regarding the cause of neonatal death was not available. This small series demonstrate that an antenatal diagnosis of fetal stroke with intraventricular hemorrhage Grades III and IV or with brain parenchymal involvement appears to be associated with poor neurologic outcome. Due to the significant neonatal neurologic impairment and potential medicolegal implications of antepartum fetal ICH, it follows that obstetricians and sonographers should be familiar with predisposing factors and typical diagnostic imaging findings of rare in utero ICH events.

Doppler, Cardiotocography, and Biophysical Profile Changes in Growth-Restricted Fetuses

To assess from diagnosis to delivery the Doppler studies of the umbilical artery, middle cerebral artery, umbilical vein, ductus venosus, and amniotic fluid index of fetuses with idiopathic growth restriction. A total of 145 singleton growth-restricted fetuses with abnormal umbilical artery pulsatility indexes were studied. Cesarean delivery was performed because of abnormal biophysical profile or nonreassuring fetal heart rate pattern. There were 4 fetal and 50 neonatal deaths. Two growth-restricted groups were identified: Group A (n = 44) included fetuses in whom all measures became abnormal preceding an abnormal biophysical profile or nonreassuring nonstress test. Group B (n = 101) included fetuses in whom 1 or more measures were normal at the time of cesarean delivery. There was no statistically significant difference in perinatal morbidity and mortality between the 2 groups. Neonatal death was increased in fetuses with umbilical artery reversed flow (odds ratio 2.34, 95% confidence interval 1.16-4.73; P < .05) and ductus venosus reversed flow (odds ratio 4.18, 95% confidence interval 2.01-8.69; P < .05). A significant correlation was also found between low birth weight and adverse perinatal outcome. In fetuses with idiopathic growth restriction, 1) low birth weight, 2) umbilical artery reversed flow, and 3) ductus venosus absent or reversed flow are associated with an increased perinatal morbidity and mortality.

Is Notching in the Umbilical Artery Doppler Waveform a Benign Finding?

Adiastolic notch in the uterine artery Doppler flow velocity waveform (FVW) is associated with an increased uterine vascular impedance, impaired uterine blood flow, and adverse perinatal outcome. 1 Likewise, uterine artery notching combined with an abnormal FVW of the umbilical artery (UA) is considered a predictor of adverse neonatal outcome. 2 Unlike data regarding the uterine artery, data are rare regarding the clinical importance of notching in the UA as an isolated finding. A few case reports have described the association between umbilical cord notching (with or without an abnormal FVW) and cord entanglement in monoamniotic twins, 3 fetal gastroschisis, 4 and fetal intra-abdominal vein dilatation. 5 Recently, Abuhamad et al 6 prospectively evaluated 1857 pregnancies and found UA notching in 29 (1.6%) fetuses. They showed that UA notching is associated with both cord and placental abnormalities, including abnormal cord insertion, cord stricture, and false or true knots in the cord. 6 Furthermore, they suggested that this finding may have important clinical implications, such as cord and placental abnormalities and a high prevalence of nonreassuring fetal heart rate abnormalities during labor. We present a case in which UA notching was detected in an impaired fetus with a single umbilical artery (SUA) whose umbilical cord was wrapped around its body. On the basis of this case and our review of the literature, we recommend increased fetal surveillance whenever FVWs display a notch in the UA.

Use of umbilical‐cerebral Doppler ratios in predicting fetal growth restriction in near‐term fetuses

To compare the sensitivity and specificity of different umbilical-cerebral ratios in the prediction and detection of fetal growth restriction in near-term fetuses when the umbilical arterial waveform is within normal. A prospective cross-sectional observational study was carried out recruiting consecutive singleton pregnancies with clinically suspected fetal growth restriction after 34 weeks gestation. The umbilical-cerebral ratios were then calculated from the S/D, RI and PI values and correlated with immediate perinatal outcome. A total of 187 patients were recruited. Twelve cases had abnormal UA Doppler flow velocity waveform studies. Of the 175 with normal UA Doppler findings, 92 (53.1%) were confirmed to have fetal growth restriction (FGR) with birth weights below the tenth centile for gestation. The detection rate of FGR by ultrasound biometry was 96.7%. The mean umbilical artery S/D, RI and PI values were higher in the fetal growth restriction group, while the middle cerebral artery values were lower as compared to fetuses with no growth restriction. A small but significant difference was seen in the umbilical-cerebral ratios of the different indices between the two groups. Receiver operator characteristic curves showed that there was little difference between the performances of the S/D, RI or PI ratios and all had limited power in predicting fetal growth restriction. In the presence of normal umbilical artery Doppler waveforms, umbilical-cerebral ratios have limited power to predict fetal growth restriction.

Normalization of a severely abnormal ductus venosus Doppler flow velocity waveform in the presence of normal arterial flow parameters

Article Normalization of a severely abnormal ductus venosus Doppler flow velocity waveform in the presence of normal arterial flow parameters was published on January 1, 2005 in the journal Journal of Perinatal Medicine (volume 33, issue 1).

Delayed normalisation of uterine artery doppler waveforms is not a benign phenomenon

Objective: To evaluate the pregnancy outcome in patients with abnormal uterine artery Doppler flow velocity waveforms (FVW’s) at 19–21 weeks, which were subsequently normal by 24–26 weeks, and to study the effect of low-dose aspirin on these waveforms. Design: The study group consisted of 49 patients who had abnormal uterine artery flow velocity waveforms (FVW’s) at 19–21 weeks. These women were initially commenced on 100 mg slow-release aspirin at 20 weeks, which was discontinued at the follow-up visit, after confirming normal uterine artery Doppler FVW. The control group consisted of 730 patients with normal uterine artery Doppler waveforms at 19–21 weeks. The main outcome measures were: small for gestational age (SGA) <10th centile, pre-eclampsia, placental abruption, and perinatal mortality rate (PMR). Results: When compared with the control group, the study group had an increased risk of placental abruption (2% versus 0.27%, P=0.05) 95% Confidence Intervals CI=0.01–0.13), low birth weight (3087 versus 3383 gm, P=0.0003), SGA <10th centile (32.7% versus 11.9%, P≤0.0001, CI=0.14–0.5), and PMR (2/49 versus 1/730, P<0.0001, CI=0.003–0.37). Conclusions: These findings suggest that delayed normalisation of the uterine artery Doppler waveform is not a benign phenomenon. This subgroup of patients is at increased risk of pregnancy complications, in particular SGA and placental abruption. These patients could benefit from serial ultrasound scans in the third trimester to evaluate fetal growth and well-being. Aspirin does not appear to play a major part in modifying uterine artery blood flow.

Maternal plasma from pregnant women with umbilical placental vascular disease does not affect endothelial cell mRNA expression of nitric oxide synthase.

In placental vascular disease identified by umbilical artery Doppler study we have shown the existence of a factor in fetal plasma that causes activation of endothelial cells in culture with expression of cell adhesion molecules and nitric oxide synthase, apoptosis, and proinflammatory cytokine production. The present work was carried out to investigate a maternal origin for this factor active in the fetal circulation. We collected maternal plasma from pregnant women with Doppler-defined umbilical placental vascular disease and examined its effect on endothelial cells in culture. Aliquots from a common culture of human umbilical vein endothelial cells (HUVEC) were incubated with maternal plasma from women with normal pregnancy (n = 23), umbilical placental vascular disease defined by abnormal umbilical artery Doppler (n = 30, with or without preeclampsia), and preeclampsia with normal umbilical artery Doppler (n = 14). The expression of mRNA for inducible and endothelial constitutive nitric oxide synthase (iNOS and ecNOS, respectively) was assessed by reverse transcriptase polymerase chain reaction. There was no significant increase in either the iNOS or the ecNOS mRNA expression by HUVEC cultured with maternal plasma from pregnancies with umbilical placental vascular disease compared with normal pregnancy (iNOS 1.49 +/- 0.35 versus 1.38 +/- 0.25; ecNOS 1.51 +/- 0.35 versus 1.25 +/- 0.27; P >.05). In the placental vascular disease group the results were similar for the presence or absence of maternal preeclampsia. In the samples from women with preeclampsia with normal umbilical Doppler, both iNOS and ecNOS mRNA expression (iNOS 1.42 +/- 0.53; ecNOS 1.46 +/- 0.39; P >.05) did not differ from normal. Maternal plasma from pregnancies with umbilical placental vascular disease did not affect endothelial cell expression of nitric oxide synthase. This finding does not support a maternal origin for the factor demonstrated in fetal plasma. These results suggest separate pathogenic pathways for the endothelial cell activation seen in preeclampsia and fetal growth restriction associated with abnormal umbilical artery Doppler flow velocity waveforms. These findings are also consistent with the concept that the vascular pathology in the fetal placenta may be primary and that the uteroplacental circulation is reduced in response rather than acts as a constraint.

Immunohistochemical localization of endothelin-1 in human placenta from normal and growth-restricted pregnancies.

The purpose of this study was to investigate whether the localization of endothelin-1 (ET-1) immunoreactivity differs in human placental tissues from third-trimester normal and intrauterine growth restricted (IUGR) pregnancies. Immunohistochemistry for ET-1 was performed on human placentas from 30 IUGR and 30 uncomplicated pregnancies matched for gestational age. The distribution and intensity of ET-1 immunoreactivity was assessed by a semiquantitative scoring system. Doppler flow velocity waveform analysis of the umbilical artery was performed in each patient before delivery. ET-1 was localized diffusely in placental specimens from normal and IUGR pregnancies. The localization of ET-1 immunoreactivity was significantly higher in the capillary endothelial cells of villi as well as in the endothelial, decidual, and trophoblastic cells of the basal plate in placentas from normal pregnancies than from IUGR pregnancies. There was no significant difference in placental ET-1 immunoreactivity between IUGR pregnancies with normal and abnormal umbilical artery Doppler flow velocity waveforms. Placental ET-1 immunoreactivity was significantly higher in the decidual and trophoblastic cells of the basal plate and the capillary endothelial cells of villi in normal pregnancies than in IUGR pregnancies with normal umbilical artery Doppler flow velocity waveforms. However, only the decidual and trophoblastic cells of the basal plate demonstrated significantly higher abundant localization of ET-1 immunoreactivity in normal pregnancies than in IUGR pregnancies with abnormal umbilical artery Doppler flow velocity waveforms. In conclusion, our findings suggest that the lower expression of ET-1 in placental tissues from IUGR pregnancies might be secondary to an adaptive mechanism to reduce the vasoconstrictor effect of ET-1.

The role of fetal nuchal translucency and ductus venosus Doppler at 11-14 weeks of gestation in the detection of major congenital heart defects.

To determine whether, in a selected high-risk population, Doppler velocimetry of the ductus venosus can improve the predictive capacity of increased nuchal translucency in the detection of major congenital heart defects in chromosomally normal fetuses at 11-14 weeks of gestation. Ductus venosus Doppler ultrasound blood velocity waveforms were obtained prospectively at 11-14 weeks of gestation in 1040 consecutive singleton pregnancies. Waveforms were classified either as normal in the presence of a positive A-wave, or as abnormal if the A-wave was absent or negative. All cases were screened for chromosomal defects by a combination of maternal age and fetal nuchal translucency thickness. In 484 cases karyotyping was performed. Those fetuses found to be chromosomally normal by prenatal cytogenetic analysis, and which had abnormally increased nuchal translucency and/or abnormal ductus venosus Doppler velocimetry, underwent fetal echocardiography at 14-16 weeks of gestation. Ultrasound examination was repeated at 22-24 weeks of gestation in all women. The sensitivity, specificity and positive and negative predictive values for the detection of major cardiac defects of increased nuchal translucency thickness alone, ductus venosus Doppler alone and increased nuchal translucency thickness in association with abnormal ductus venosus Doppler were determined. In 29 of 998 fetuses presumed to be chromosomally normal, reversed or absent flow during atrial contraction was associated with increased (> 95(th) centile for crown-rump length) nuchal translucency. Major cardiac defects were observed in 9 of these 29 fetuses. No other major cardiac abnormalities were found in chromosomally normal fetuses in spite of the presence of either increased nuchal translucency alone or abnormal ductus venosus velocimetry. A total of 25 cardiac malformations were observed in the population. Fifteen were associated with aneuploidy and 10 fetuses had a normal karyotype. Nine of the 10 had major cardiac anomalies and one had a ventricular septal defect. The nine cases with normal karyotype and major cardiac anomalies had both increased nuchal translucency and abnormal ductus venosus flow velocity waveforms. In chromosomally normal fetuses with increased nuchal translucency, assessment of ductus venosus blood flow velocimetry could improve the predictive capacity for an underlying major cardiac defect.

Decreased vascularization and cell proliferation in placentas of intrauterine growth–restricted fetuses with abnormal umbilical artery flow velocity waveforms

Objective: The purpose of this study was to compare the morphologic features of placentas in severe intrauterine fetal growth restriction with abnormal umbilical artery blood flow velocity waveforms and normal gestation. Study Design: Immunohistochemical methods were used to evaluate cell proliferation, vascular density, and α-smooth muscle actin expression by stromal cells in a group of 9 age-matched intrauterine growth–restricted and control placentas at 25 to 41 weeks of gestation. Results: Fewer MIB1-positive nuclei were observed in both trophoblast and stromal cell populations in intrauterine growth restriction, which indicates fewer cells in cycle. Furthermore, a greatly reduced vascular density was observed, along with higher levels of α-smooth muscle actin expression in stromal cells. Conclusion: Intrauterine growth–restricted placentas show reduced cell proliferation in both trophoblast and stromal cell compartments. Peripheral villous vascularization is highly reduced. (Am J Obstet Gynecol 2002;187:764-9.)

Second-trimester uterine artery Doppler screening in unselected populations: a review

Objective: Doppler ultrasound provides a non-invasive method for the study of the uteroplacental circulation. In normal pregnancy, impedance to flow in the uterine arteries decreases with gestation,which may be the consequence of trophoblastic invasion of the spiral arteries and their conversion into low-resistance vessels. Pre-eclampsia and fetal growth restriction are associated with failure oftrophoblastic invasion of spiral arteries, and Doppler studies, in these conditions, have shown that impedance to flow in the uterine arteries is increased. A series of screening studies involving assessmentof impedance to flow in the uterine arteries have examined the potential value of Doppler in identifying pregnancies at risk of the complications of impaired placentation. This review examines the findingsof Doppler studies in unselected populations.Methods: Searches of a computerized medical database were performed to identify relevant studies. Only those studies that provided sufficient datato allow calculation of the performance of the test were included in the analysis. Likelihood ratios were calculated for each study and are reported for pre-eclampsia, fetal growth restriction and perinataldeath as well as for more severe forms of pre-eclampsia and fetal growth restriction.Results: The literature search identified 19 relevant studies, four of which were excluded from the furtheranalysis. The main characteristics and results of the 15 remaining studies provided discrepant results, which may be the consequence of differences in Doppler technique for sampling, the definition of abnormalflow velocity waveform, differences in the populations examined, the gestational age at which women were studied and different criteria for the diagnosis of pre-eclampsia and fetal growth restriction. Nevertheless,the studies provided evidence that increased impedance to flow in the uterine arteries is associated with increased risk for subsequent development of pre-eclampsia, fetal growth restriction and perinataldeath. In addition, women with normal impedance to flow in the uterine arteries constituted a group that have a low risk of developing obstetric complications related to uteroplacental insufficiency.Conclusions:The review suggests that increased impedance to flow in the uterine arteries in pregnancies attending for routine antenatal care identifies about 40% of those who subsequently develop pre-eclampsia andabout 20% of those who develop fetal growth restriction. Following a positive test, the likelihood of these complications is increased by about 6 and 3.5 times, respectively.

Diagnosis and prognostic value Doppler flow velocity waveform in high risk pregnancies

Objective: To determine whether Doppler umbilical artery flow velocity waveforms (FVW) would improve the clinical management and reduce the prenatal morbidity or not, in cases of high risk pregnancies.Methods: A total of 160 pregnant women of 28 weeks or more gestational age were included in this study. The age of the cases were from 20‐ to 30‐year‐old and their gravidity ranged from gravida 1 to 5. The cases were classified into two groups. Low risk group, not associated with medical or obstetric complications and includes 70 cases. High risk groups include, the other 90 cases, such as the following: mild pre‐eclampsia (20), severe pre‐eclampsia (15), diabetes mellitus (10), postdated pregnancy (15), previous one or more cesarean section (15), rheumatic heart (4), decreased perception of fetal movement (3), bronchial asthma (2), Rh incompatibility (2) and previous IUFD. All of them were subjected to thorough general and obstetric examination, investigations, ultrasonic examination, biophysical profile scoring and Doppler umbilical artery FVW study. The cases of low risk group were examined every 2 weeks, while high risk ones, were examined every week or twice weekly according to the results of the previous examination.Results: There is a highly significant difference between values of umbilical artery FVW indices in low and high risk group. Doppler has specificity 92.8% in cases of low risk group while has sensitivity 52.8% and specificity 55.6% in cases of high risk group and it is more sensitive than biophysical profile. Doppler of umbilical artery is very beneficial in cases of pre‐eclampsia, where its sensitivity 78.5% and its specificity 52%.Conclusion: There is a strong association between abnormal FVW and adverse fetal outcome. The Doppler will identify a group of fetuses truly at risk, where intensive fetal monitoring or delivery will be required.