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1.
S Afr Med J ; 109(5): 347-352, 2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31131803

RESUMO

BACKGROUND: In South Africa (SA), the largest category of perinatal deaths is unexplained stillbirths. Two-thirds of these occur in the antenatal period and most fetuses are macerated, but at antenatal clinics the mothers were generally regarded as healthy, with low-risk pregnancies. Innovative methods are urgently required to detect fetuses at risk of stillbirth and manage the mothers appropriately. OBJECTIVES: To determine the prevalence of raised resistance indices (RIs) of the umbilical artery in a low-risk, low-income population and ascertain whether use of this information can prevent perinatal deaths. METHODS: A descriptive study was performed in Mamelodi township, east of Pretoria, SA, on pregnant women attending antenatal clinics draining to two community health centres (CHCs). These women, classified as having low-risk pregnancies, were screened for placental insufficiency using a continuous-wave Doppler ultrasound apparatus (Umbiflow) between 28 and 32 weeks' gestation. When a raised RI was detected, the mother was referred to a high-risk clinic and managed according to a standard protocol. A cohort analytical study compared women who attended antenatal care at the same clinics as the Umbiflow group but did not have an Umbiflow test with those who had an Umbiflow test. The outcomes of all the deliveries in Mamelodi were recorded. The prevalences of abnormal RIs, absent end-diastolic flow (AEDF), stillbirths and neonatal deaths were the main outcome measures. RESULTS: An Umbiflow RI was performed in 2 868 women, and pregnancy outcome was available for 2 539 fetuses (88.5%); 297 fetuses (11.7%) were regarded as at high risk. AEDF was found in 1.5% of the population screened with an outcome. There were 29 perinatal deaths in the Umbiflow group (low risk n=18, high risk n=11). The perinatal mortality rate for 12 168 women attending the CHCs and the antenatal clinics draining to the CHCs who did not have an RI was 21.3/1 000 births, significantly higher than that in the Umbiflow group (11.4/1 000 births) (risk ratio 0.58, 95% confidence interval 0.42 - 0.81). CONCLUSIONS: The prevalence of AEDF in this low-risk population is ~10 times higher than that previously recorded. Use of the information prevented a number of perinatal deaths, most of which would have been macerated stillbirths. Screening a low-risk pregnant population using continuous-wave Doppler ultrasound may substantially reduce the prevalence of unexplained stillbirths in SA.


Assuntos
Programas de Rastreamento/métodos , Cuidado Pré-Natal/métodos , Gestão de Riscos/métodos , Ultrassonografia Doppler/métodos , Ultrassonografia Pré-Natal/métodos , Artérias Umbilicais/diagnóstico por imagem , Resistência Vascular/fisiologia , Adulto , Feminino , Seguimentos , Idade Gestacional , Humanos , Recém-Nascido , Mortalidade Perinatal/tendências , Pobreza , Gravidez , Resultado da Gravidez , Fluxo Sanguíneo Regional/fisiologia , Fatores de Risco , África do Sul/epidemiologia , Taxa de Sobrevida/tendências , Artérias Umbilicais/fisiopatologia , Adulto Jovem
2.
Int J Gynaecol Obstet ; 144(2): 174-179, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30471100

RESUMO

OBJECTIVE: To compare Doppler ultrasonographic measurements of the fetal middle cerebral artery peak systolic velocity (MCA PSV) among women with or without gestational diabetes mellitus (GDM). METHODS: A cross-sectional study was conducted among pregnant women who presented for prenatal care at a single hospital in Brazil between September 11, 2015, and January 6, 2017. Patients were stratified into a group with GDM and a control group without GDM. One Doppler ultrasonographic assessment was performed per participant. This measurement was made after diagnosis but before the start of treatment among women in the GDM group. Fetal ultrasonographic and biometric variables assessed included MCA PSV, MCA pulsatility index, umbilical artery pulsatility index, the MCA-to-umbilical artery ratio, abdominal circumference, and weight. RESULTS: The study included 238 women: 115 in the GDM group and 123 in the control group. The median MCA PSV was 1.02 in the GDM group and 1.08 in the control group (P=0.036). No statistically significant between-group differences were found for the other fetal ultrasonographic variables or for the fetal biometric variables assessed. None of the maternal or fetal parameters assessed displayed a linear correlation with MCA PSV. CONCLUSION: Doppler ultrasonographic measurements of MCA PSV were lowered among the fetuses of women diagnosed with GDM.


Assuntos
Diabetes Gestacional/fisiopatologia , Artéria Cerebral Média/diagnóstico por imagem , Artérias Umbilicais/diagnóstico por imagem , Adulto , Velocidade do Fluxo Sanguíneo , Brasil , Estudos de Casos e Controles , Estudos Transversais , Feminino , Feto/irrigação sanguínea , Humanos , Artéria Cerebral Média/embriologia , Artéria Cerebral Média/fisiopatologia , Gravidez , Cuidado Pré-Natal , Ultrassonografia Doppler , Ultrassonografia Pré-Natal , Artérias Umbilicais/irrigação sanguínea , Artérias Umbilicais/fisiopatologia
3.
J Perinat Med ; 47(2): 212-217, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30210056

RESUMO

Background As conflicting results have been reported about the association of reversed flow on the aortic isthmus (AoI) and adverse perinatal results in fetal growth restriction (FGR), we aim to compare perinatal outcomes (including tolerance to labor induction) of late-onset FGR between those with anterograde and reversed AoI flow. Methods This was an observational retrospective cohort study on 148 singleton gestations diagnosed with late-onset FGR (diagnosis ≥32+0 weeks), with an estimated fetal weight (EFW) <10th centile and mild fetal Doppler alteration: umbilical artery (UA) pulsatility index (PI) >95th centile, middle cerebral artery (MCA)-PI <5th centile or cerebral-placental ratio <5th centile. Anterograde AoI flow was present in n=79 and reversed AoI flow in n=69. Delivery was recommended from 37 weeks in both groups. Perinatal results were compared between the groups. Results The global percentage of vaginal delivery of fetuses with anterograde and reversed blood flow was 55.7% vs. 66.7% (P=0.18) and the percentage of cesarean section (C-section) for non-reassuring fetal status was 12.7% vs. 15.9% (P=0.29), respectively. When evaluating those that underwent labor induction, the vaginal delivery rate was 67.9% vs. 77.2% (P=0.17), respectively. There were no significant differences regarding any other perinatal variables and there were no cases of severe morbidity or mortality. Conclusion We observed that the presence of reversed AoI flow does not worsen perinatal outcomes on fetuses with late-onset growth restriction with mild Doppler alterations. Attempt of labor induction is feasible in these fetuses regardless of the direction of AoI flow.


Assuntos
Aorta Torácica , Retardo do Crescimento Fetal , Artéria Cerebral Média , Ultrassonografia Doppler/métodos , Ultrassonografia Pré-Natal/métodos , Artérias Umbilicais , Adulto , Aorta Torácica/diagnóstico por imagem , Aorta Torácica/fisiopatologia , Cesárea/estatística & dados numéricos , Feminino , Retardo do Crescimento Fetal/diagnóstico , Retardo do Crescimento Fetal/etiologia , Retardo do Crescimento Fetal/fisiopatologia , Peso Fetal , Feto/irrigação sanguínea , Humanos , Trabalho de Parto Induzido/estatística & dados numéricos , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiopatologia , Placenta/diagnóstico por imagem , Valor Preditivo dos Testes , Gravidez , Terceiro Trimestre da Gravidez , Espanha , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia
4.
J Matern Fetal Neonatal Med ; 27(3): 247-51, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23758482

RESUMO

OBJECTIVE: In order to more accurately assess fetal neurological status in five fetuses with severe intrauterine growth restriction (IUGR), combined assessment of their hemodynamics and motor activity was undertaken in this study. METHOD: Hemodynamic changes in the placental and fetal cerebral vessels were evaluated using the umbilical artery resistance index (URI), and the middle cerebral artery resistance index (CRI). The blood flow redistribution towards the fetal brain in response to fetal hypoxia was detected by the C/U (cerebro - umbilical) ratio, expressed as CRI/URI. Motoric parameters were assessed by new antenatal neurologic scoring test named Kurjak Antenatal Neurodevelopmental Test (KANET), based on evaluation of spontaneous motor activity using four-dimensional (4D) ultrasound. RESULTS: KANET has potential in recognizing pathologic and borderline behavior in IUGR fetuses with or without blood flow redistribution towards the fetal brain. Very low values of C/U ratio and abnormal KANET score have indicated adverse pregnancy outcome. CONCLUSION: In some pregnancies complicated with IUGR, estimation of the risk of hypoxia versus prematurity can be extremely puzzling. Combined assessment of hemodynamic and motoric parameters in IUGR fetuses could allow construction of an algorithm, which would be helpful in the decision making process of pregnancy termination.


Assuntos
Retardo do Crescimento Fetal/fisiopatologia , Hemodinâmica , Artéria Cerebral Média/fisiopatologia , Atividade Motora , Ultrassonografia Pré-Natal/métodos , Artérias Umbilicais/fisiopatologia , Técnicas de Apoio para a Decisão , Feminino , Retardo do Crescimento Fetal/diagnóstico por imagem , Hipóxia Fetal/diagnóstico por imagem , Hipóxia Fetal/fisiopatologia , Humanos , Masculino , Artéria Cerebral Média/diagnóstico por imagem , Gravidez , Artérias Umbilicais/diagnóstico por imagem
5.
Am J Obstet Gynecol ; 206(4): 300-8, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22464066

RESUMO

OBJECTIVE: We sought to provide evidence-based guidelines for utilization of Doppler studies for fetuses with intrauterine growth restriction (IUGR). METHODS: Relevant documents were identified using PubMed (US National Library of Medicine, 1983 through 2011) publications, written in English, which describe the peripartum outcomes of IUGR according to Doppler assessment of umbilical arterial, middle cerebral artery, and ductus venosus. Additionally, the Cochrane Library, organizational guidelines, and studies identified through review of the above were utilized to identify relevant articles. Consistent with US Preventive Task Force suggestions, references were evaluated for quality based on the highest level of evidence, and recommendations were graded. RESULTS AND RECOMMENDATIONS: Summary of randomized and quasirandomized studies indicates that, among high-risk pregnancies with suspected IUGR, the use of umbilical arterial Doppler assessment significantly decreases the likelihood of labor induction, cesarean delivery, and perinatal deaths (1.2% vs 1.7%; relative risk, 0.71; 95% confidence interval, 0.52-0.98). Antepartum surveillance with Doppler of the umbilical artery should be started when the fetus is viable and IUGR is suspected. Although Doppler studies of the ductus venous, middle cerebral artery, and other vessels have some prognostic value for IUGR fetuses, currently there is a lack of randomized trials showing benefit. Thus, Doppler studies of vessels other than the umbilical artery, as part of assessment of fetal well-being in pregnancies complicated by IUGR, should be reserved for research protocols.


Assuntos
Retardo do Crescimento Fetal/diagnóstico por imagem , Ultrassonografia Doppler/métodos , Velocidade do Fluxo Sanguíneo , Feminino , Coração Fetal/diagnóstico por imagem , Coração Fetal/fisiopatologia , Humanos , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiopatologia , Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto , Ultrassonografia Pré-Natal/métodos , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia
6.
J Matern Fetal Neonatal Med ; 25(10): 1941-4, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22489827

RESUMO

OBJECTIVE: To develop and analyze a fetal risk assessment score (FRAS) that incorporates fetal arterial and venous blood flow studies (BFS), amniotic fluid volume, the non-stress test (NST) and an estimated fetal weight to improve the ability of antenatal testing to identify fetuses at risk for poor perinatal outcome and compare it to the Biophysical Profile (BPP). STUDY DESIGN: The Perinatal data base of the author's institution was searched for all patients with singleton gestation with the diagnosis of intrauterine growth restriction, and who had both a biophysical profile (BPP) and fetal BFS (umbilical and middle cerebral artery, ductus venosus) within 4 days of delivery. Fetuses with major congenital abnormalities, chromosomal anomalies, or who delivered less than 25 weeks gestation were excluded. A FRAS score was developed by assigning numerical points for increasing abnormal arterial and venous BFS, and one point each for a non-reactive NST, oligohydramnios or if the fetus was small for gestational age. Recommendations for delivery were based on the clinical situation and the results of the Biophysical Profile (BPP); the FRAS score was not available to the attending physician. The FRAS was then compared to the BPP for the prediction of poor neonatal outcome (significant neonatal complications or prolonged hospital stay) using receiver operating characteristic (ROC) curve analysis and χ(2) analysis. RESULTS: Two hundred twenty-nine patients were included in the study. The results of the ROC analysis showed that the designed FRAS (area: 0.802) was slightly better than the BPP (area: 0.659) at predicting poor perinatal outcome in a group of growth-restricted fetuses. CONCLUSION: The study gives support to the hypothesis that combining biophysical tests with BFS will improve the identification of potential high-risk patients at increased risk for poor neonatal outcome, but prospective, randomized studies are needed to confirm this hypothesis.


Assuntos
Técnicas de Apoio para a Decisão , Retardo do Crescimento Fetal/fisiopatologia , Doenças do Recém-Nascido/diagnóstico , Artéria Cerebral Média/fisiopatologia , Ultrassonografia Doppler , Ultrassonografia Pré-Natal , Artérias Umbilicais/fisiopatologia , Adolescente , Adulto , Líquido Amniótico , Distribuição de Qui-Quadrado , Feminino , Retardo do Crescimento Fetal/diagnóstico por imagem , Peso Fetal , Humanos , Recém-Nascido , Doenças do Recém-Nascido/epidemiologia , Doenças do Recém-Nascido/etiologia , Tempo de Internação , Artéria Cerebral Média/diagnóstico por imagem , Gravidez , Prognóstico , Curva ROC , Estudos Retrospectivos , Medição de Risco , Artérias Umbilicais/diagnóstico por imagem , Adulto Jovem
7.
Ultraschall Med ; 33(7): E16-E24, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22161615

RESUMO

Noninvasive blood flow measurements based on Doppler ultrasound studies are the main clinical tool for studying the cardiovascular status of fetuses at risk for circulatory compromise. Usually, qualitative analysis of peripheral arteries and in particular clinical situations such as severe growth restriction or volume overload also of venous vessels close to the heart or of flow patterns in the heart is being used to gauge the level of compensation in a fetus. However, quantitative assessment of the driving force of the fetal circulation, the cardiac output remains an elusive goal in fetal medicine. This article reviews the methods for direct and indirect assessment of cardiac function and explains new clinical applications. Part 1 of this review describes the concept of cardiac function and cardiac output and the techniques that have been used to quantify output. Part 2 summarizes the use of arterial and venous Doppler studies in the fetus and gives a detailed description of indirect measurements of cardiac function (like indices derived from the duration of segments of the cardiac cycle) with current examples of their application.


Assuntos
Débito Cardíaco/fisiologia , Ecocardiografia Doppler/métodos , Retardo do Crescimento Fetal/diagnóstico por imagem , Retardo do Crescimento Fetal/fisiopatologia , Cardiopatias Congênitas/diagnóstico por imagem , Cardiopatias Congênitas/fisiopatologia , Ultrassonografia Pré-Natal/métodos , Velocidade do Fluxo Sanguíneo/fisiologia , Encéfalo/irrigação sanguínea , Feminino , Transfusão Feto-Fetal/diagnóstico por imagem , Transfusão Feto-Fetal/fisiopatologia , Insuficiência Cardíaca/congênito , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/fisiopatologia , Hérnia Diafragmática/diagnóstico por imagem , Hérnia Diafragmática/fisiopatologia , Hérnias Diafragmáticas Congênitas , Humanos , Recém-Nascido , Doenças do Prematuro/diagnóstico por imagem , Doenças do Prematuro/fisiopatologia , Contração Miocárdica/fisiologia , Placenta/irrigação sanguínea , Insuficiência Placentária/diagnóstico por imagem , Insuficiência Placentária/fisiopatologia , Gravidez , Fluxo Sanguíneo Regional/fisiologia , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia , Veias Umbilicais/diagnóstico por imagem , Veias Umbilicais/fisiopatologia
8.
Nutr Metab Cardiovasc Dis ; 21(1): 54-61, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19819678

RESUMO

BACKGROUND AND AIMS: Periconception folic acid supplementation may influence early placentation processes and thereby the occurrence of hypertensive pregnancy disorders. For this reason we examined the associations between periconception folic acid supplementation and uteroplacental vascular resistance, blood pressure, and the risks of gestational hypertension and preeclampsia, in 5993 pregnant women, participating in a population-based cohort study. METHODS AND RESULTS: Folic acid supplementation was assessed by questionnaire. Mean pulsatility index (PI) and resistance index (RI) of the uterine (UtA) and umbilical arteries (UmA) were measured by Doppler ultrasound in mid- and late pregnancy. Systolic and diastolic blood pressures (SBP, DBP) were measured in early, mid- and late pregnancy. Compared to women who did not use folic acid, preconception folic acid users had a slightly lower UtA-RI in mid-pregnancy [ß -0.02, 95% confidence interval (CI) -0.03, -0.01] and late pregnancy [ß -0.02, 95% CI -0.03, -0.001], a lower UtA-PI in mid-pregnancy [ß -0.06, 95% CI -0.1, -0.03] and late pregnancy [ß -0.03, 95% CI -0.05, -0.01], as well as tendencies towards a lower UmA-PI in mid-pregnancy [ß -0.02, 95% CI -0.04, -0.001] and late pregnancy [ß -0.01, 95% CI -0.02, 0.01]. Additionally, these women had slightly higher SBP and DBP throughout pregnancy. Neither the patterns of blood-pressure change during pregnancy, nor the risk of gestational hypertension and preeclampsia differed between the folic acid categories. CONCLUSION: Periconception folic acid supplementation is associated with lower uteroplacental vascular resistance and higher blood pressures during pregnancy. The effects are small and within physiologic ranges and seem not associated with the risk of hypertensive pregnancy disorders.


Assuntos
Ácido Fólico/farmacologia , Circulação Placentária/efeitos dos fármacos , Resistência Vascular/efeitos dos fármacos , Vitaminas/farmacologia , Adolescente , Adulto , Pressão Sanguínea/efeitos dos fármacos , Estudos de Coortes , Suplementos Nutricionais , Feminino , Idade Gestacional , Humanos , Hipertensão Induzida pela Gravidez/epidemiologia , Hipertensão Induzida pela Gravidez/fisiopatologia , Pré-Eclâmpsia/epidemiologia , Gravidez , Trimestres da Gravidez , Fatores Socioeconômicos , Ultrassonografia , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia , Adulto Jovem
9.
Ginekol Pol ; 77(3): 190-6, 2006 Mar.
Artigo em Polonês | MEDLINE | ID: mdl-16871836

RESUMO

OBJECTIVES: Umbilical venous pulsation is an important sign of hemodynamic compromise, especially during fetal heart failure and asphyxia. DESIGN: The aim of this study was to determine of the blow flow in the middle cerebral artery and the umbilical artery in fetuses with umbilical venous pulsations. MATERIALS AND METHODS: The investigation included 18 fetuses with signs of the intrauterine growth restriction and umbilical venous pulsations after 28th weeks of gestation. We evaluated cerebral-placental ratio (CPR) and pulsation index (PI) in the middle cerebral artery (MCA) and the umbilical artery (UA). RESULTS: We observed brain sparring effect in all cases of analyzing fetuses. There were 77,8% of abnormal flow pattern in umbilical artery. 13 fetuses had a single pulsation pattern in umbilical vein and another 5 had double pulsation pattern. CONCLUSIONS: The coexistence of umbilical vein pulsation and abnormal flow pattern in umbilical artery is closely related to increased perinatal mortality.


Assuntos
Retardo do Crescimento Fetal/diagnóstico por imagem , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiopatologia , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia , Asfixia Neonatal/diagnóstico por imagem , Asfixia Neonatal/prevenção & controle , Feminino , Feto/irrigação sanguínea , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/prevenção & controle , Humanos , Recém-Nascido , Fluxo Pulsátil , Fluxo Sanguíneo Regional , Ultrassonografia Doppler , Ultrassonografia Pré-Natal
10.
Pediatrics ; 105(2): 385-91, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10654960

RESUMO

OBJECTIVE: After intrauterine growth restriction we found at the age of 6 months an acceleration of neurophysiologic maturation. However, at later ages impaired cognitive outcome has been reported. Therefore, we investigated in children with and without fetal hemodynamic adaptation to intrauterine growth restriction whether the accelerated neurophysiologic maturation in infancy might be associated with impaired cognitive outcome at preschool age. DESIGN: At 5 years of age cognitive function was assessed using the Revision of the Amsterdam Children's Intelligence Test in 73 preterm infants (26-33 weeks) who were prospectively followed from the antenatal period up to the age of 5 years. Maternal educational level was used as a background variable to estimate the confounding effects of socioeconomic status on cognitive function. Fetal Doppler studies were performed and the umbilical artery pulsatility index (PI) divided by the middle cerebral artery PI ratio (U/C ratio) was calculated. A U/C ratio >0.725 was considered as an indication of fetal cerebral hemodynamic adaptation to a compromised placental perfusion, ie, fetal brain-sparing. Visual-evoked potentials (VEPs) were recorded at 6 months and 1 year of age. In addition, data on neurologic status at 3 years were available. RESULTS: Mean IQ score was significantly lower for children born with a raised U/C ratio (87 +/- 16) compared with children with a normal U/C ratio (96 +/- 17). VEP latencies decreased significantly in infants with a normal U/C ratio, whereas no decrease was found in infants with a raised U/C ratio. Variables contributing significantly to the variance of cognitive function were: U/C group, VEP latency maturation, level of maternal education, and neurodevelopmental outcome at 3 years. The linear regression model explained 33% of the variance in cognitive function. CONCLUSIONS: Both being born with a raised U/C ratio and an acceleration of VEP latencies are negatively associated with cognitive outcome at 5 years of age. Fetal brain-sparing, although a seemingly beneficial adaptive mechanism for intact neurologic survival, is, however, later associated with a poorer cognitive outcome.


Assuntos
Circulação Cerebrovascular , Desenvolvimento Infantil , Cognição , Potenciais Evocados Visuais , Recém-Nascido Prematuro , Adaptação Fisiológica , Velocidade do Fluxo Sanguíneo , Encéfalo/crescimento & desenvolvimento , Artérias Cerebrais/diagnóstico por imagem , Artérias Cerebrais/fisiopatologia , Pré-Escolar , Ecoencefalografia , Retardo do Crescimento Fetal/diagnóstico por imagem , Retardo do Crescimento Fetal/fisiopatologia , Seguimentos , Humanos , Recém-Nascido , Testes de Inteligência , Estudos Prospectivos , Fatores Socioeconômicos , Ultrassonografia Doppler , Ultrassonografia Pré-Natal , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia
11.
Ultrasound Obstet Gynecol ; 9(5): 330-8, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9201877

RESUMO

During a 20-month period we studied 175 pregnant women at high risk for hypertensive disorders of pregnancy or intrauterine growth retardation, and 172 patients at low risk, in a prospectively designed cross-sectional trial. Using duplex pulsed wave Doppler ultrasound, we recorded blood velocity waveforms from both main uterine arteries, the uteroplacental arteries in the region of placental implantation and the umbilical artery at 21-24 weeks of gestation. Persistent notches in the main stem uterine arteries and elevated resistance indices of > 0.68 in the uterine arteries and > 0.38 in the uteroplacental arteries were defined as abnormal waveforms. The incidence of proteinuric pregnancy-induced hypertension (PPIH) and intrauterine growth retardation (IUGR) were recorded as main outcome measures. Doppler proved to be more efficient at predicting a complicated pregnancy in those patients who were at high risk: a positive medical history alone was associated with a three-fold greater risk of developing PPIH and/or IUGR. In the high-risk group a single pathological Doppler sign accounted for an additional three- to four-fold increased risk, and the combination of all three pathological signs, a seven-fold additional risk for later disease. In this group PPIH and/or IUGR was found in 58.3%, compared to 8.3% if Doppler results were normal. The criterion for the definition of pathological Doppler results, whether persistent notching, the resistance index (RI) of the main stem uterine artery, or the RI in the arteries of the uteroplacental bed, was of minor importance, as all Doppler parameters were strongly correlated. However, the combination of all parameters was superior to a single parameter, and a bilateral notch was superior to a unilateral notch in terms of minimizing false-positive results. However, Doppler was less powerful in the population at low risk. Here PPIH and/or IUGR was seen in 6.1-6.4% in the group with abnormal Doppler findings compared to 5.2% in pregnancies with normal findings. None of the patients showed bilateral notching. In conclusion, pathological Doppler velocimetry of the uterine and uteroplacental circulation was a powerful predictor of PPIH and/or IUGR in high-risk pregnancies, identifying a group in which 58.3% would suffer from disease later in pregnancy. A combination of several Doppler parameters was superior to a single parameter, although the parameters were strongly correlated with each other.


Assuntos
Retardo do Crescimento Fetal/fisiopatologia , Circulação Placentária/fisiologia , Pré-Eclâmpsia/fisiopatologia , Ultrassonografia Doppler , Ultrassonografia Pré-Natal/métodos , Útero/irrigação sanguínea , Velocidade do Fluxo Sanguíneo/fisiologia , Estudos Transversais , Feminino , Retardo do Crescimento Fetal/diagnóstico por imagem , Retardo do Crescimento Fetal/etiologia , Seguimentos , Idade Gestacional , Humanos , Placenta/irrigação sanguínea , Placenta/diagnóstico por imagem , Placenta/fisiopatologia , Pré-Eclâmpsia/diagnóstico por imagem , Pré-Eclâmpsia/etiologia , Valor Preditivo dos Testes , Gravidez , Resultado da Gravidez , Segundo Trimestre da Gravidez , Estudos Prospectivos , Fatores de Risco , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia , Útero/diagnóstico por imagem , Útero/fisiopatologia
12.
Ultrasound Med Biol ; 21(7): 861-70, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7491742

RESUMO

The objective of the present study was to validate one or a combination of fetal Doppler parameters in order to assess acute fetal hypoxia in an ovine model. Acute hypoxia was induced by reducing umbilical, or maternal aortic flow (approx. 70%). A CW Doppler probe was fixed on the fetal cervical skin, facing the internal carotid artery and the fetal abdominal skin adjacent to the umbilical arteries. (The angle between Doppler beam and flow vector remained constant.) A "Doptek 3000" spectrum analyser was used to measure the maximal and mean Doppler frequencies. Heart rate (HR), umbilical blood flow (UBF), carotid blood flow (CBF), umbilical RI (URI), cerebral RI (CRI) and cerebroplacental ratio (CPR = CRI/URI) were calculated in real time. A catheter was inserted into the fetal femoral artery, for blood gas (PO2, PCO2 pH) and blood pressure (BP) measurements. After 1 min of aorta compression (70% aortic flow reduction), the URI increased by 10% (P < 0.05), and the UBF decreased by 10% (P < 0.05), but the CRI decreased by 20% (P < 0.02), and the CBF did not change significantly. Fetal PO2 and CPR fell down after 1 min (59% and 38%, respectively; P < 0.001), although strong fetal heart rate decelerations were observed. The blood pressure, PCO2 and pH did not change significantly during this test. Throughout the 12 min of cord compression (70% umbilical flow reduction) the URI increased (70% to 80% P < 0.001), and the UBF decreased (approx. 60%; P < 0.001), but the CRI decreased (approx. 25%; P < 0.01), and the CBF remained constant (+/- 5%; ns). Fetal PO2 and CPR all decreased during the compression (30% to 44% and 40% to 60%, respectively; P < 0.001). HR, pH and PCO2 did not change significantly. During cord compression the blood pressure did not change significantly. In both cases, the CPR decreased significantly (P < 0.001) with the PO2 in the same direction and with a comparable amplitude (-30% to -50%). Nevertheless, the drop in CPR was greater during cord compression than during aorta compression, probably because the compression of the cord induced a central hypovolemia in addition to the hypoxia. The CPR was found to be the hemodynamic parameter that followed most closely the PO2 acute changes. The amplitude of the variations of this parameter (-30% to -50%) were quite similar to those of the PO2 during the period of acute hypoxia.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Circulação Cerebrovascular , Sangue Fetal/química , Hipóxia Fetal/fisiopatologia , Oxigênio/sangue , Ultrassonografia Doppler , Artérias Umbilicais/fisiopatologia , Doença Aguda , Animais , Velocidade do Fluxo Sanguíneo , Feminino , Hipóxia Fetal/sangue , Hipóxia Fetal/diagnóstico por imagem , Frequência Cardíaca , Circulação Placentária , Gravidez , Ovinos , Ultrassonografia Pré-Natal , Artérias Umbilicais/diagnóstico por imagem
13.
Br J Obstet Gynaecol ; 100(8): 733-41, 1993 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8399011

RESUMO

OBJECTIVE: To assess the effect on obstetric practice of clinician access to umbilical artery Doppler ultrasound results. DESIGN: Randomised controlled trial. SETTING: A large teaching hospital. SUBJECTS: Two thousand two hundred and eighty-nine pregnancies defined as being at risk by referral for Doppler or fetal monitoring. INTERVENTIONS: Continuous wave Doppler studies of umbilical artery. Results immediately available to clinicians. MAIN OUTCOME MEASURES: Fetal outcome: perinatal mortality, Apgar score and admission to the neonatal unit. Obstetric intervention: admission to hospital, induction of labour and caesarean section. Use of of fetal well being: cardiotocography, biophysical profile and ultrasound biometry. RESULTS: The treatment and control groups were comparable in age, parity, gestation at point of entry and risk features. There were no overall differences in perinatal outcome, obstetric intervention or use of fetal monitoring. Examination of a subset recruited only because of hypertension or suspected intrauterine growth retardation (n = 754) similarly showed no difference attributable to group randomisation. Comparison of only those pregnancies retrospectively defined as low risk and high risk showed more use of cardiotocography in the high risk group with access to Doppler (P = 0.007) but no difference in the low risk group. CONCLUSION: Doppler umbilical artery recording has been shown to perform well in prediction power of antenatal fetal compromise. What has been examined in this study is the response of clinicians to the test. The results suggest that obstetricians do not use the test to modify their risk assessment, and, therefore, the need for fetal monitoring in particular pregnancies. There is a real need for accumulation of information from very large data sets, particularly in the prediction power of Doppler for antenatal fetal compromise from apparently chronic utero-placental cause to guide use of monitoring resources. If simply added to existing fetal monitoring techniques in a hospital where these are widely used, then umbilical artery Doppler recordings may at present simply involve extra resources of staff and expenses, without benefit.


Assuntos
Doenças Fetais/diagnóstico por imagem , Avaliação da Tecnologia Biomédica , Ultrassonografia Pré-Natal , Artérias Umbilicais/diagnóstico por imagem , Adulto , Peso ao Nascer , Velocidade do Fluxo Sanguíneo , Feminino , Doenças Fetais/fisiopatologia , Monitorização Fetal , Humanos , Unidade Hospitalar de Ginecologia e Obstetrícia , Gravidez , Fatores de Risco , Escócia , Artérias Umbilicais/fisiopatologia
14.
Gynakologe ; 26(1): 29-34, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8468031

RESUMO

Assessment of the fetal condition is an important but also difficult problem. During the last decades a number of new fetal monitoring techniques have been introduced into clinical practice without proper evaluation regarding its value for clinical practice beforehand. The last fetal monitoring technique introduced into clinical practice in such a way is the assessment of the fetal condition with umbilical artery flow velocity waveform analyses. Although in cases with zeroflow or reverse flow during diastole the complication rate is high, it is not possible to assess the fetal oxygenation by means of recording the umbilical artery pulsatility index and its changes. Moreover no adequate treatment of fetal hypoxia is yet available, except termination of pregnancy. It is important in this context to realize that prematurity in itself is still the most powerful determining factor for the further development of the child.


Assuntos
Retardo do Crescimento Fetal/diagnóstico por imagem , Troca Materno-Fetal/fisiologia , Ultrassonografia Pré-Natal , Animais , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Retardo do Crescimento Fetal/fisiopatologia , Hipóxia Fetal/diagnóstico por imagem , Hipóxia Fetal/fisiopatologia , Humanos , Recém-Nascido , Gravidez , Prognóstico , Ovinos , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia , Resistência Vascular/fisiologia
15.
Ultrasound Med Biol ; 18(1): 97-103, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1566530

RESUMO

If the fetal Doppler examination during human pregnancies provides useful information to the obstetrician, it does not allow us to collect all the biological and haemodynamic data required to understand the physiopathological mechanisms involved in the development of intrauterine growth retardation (IUGR) and hypoxia. With the animal model, it is possible to have access to the blood pressure, the blood velocity and volume, to collect blood sampling and to perform pharmacological tests, or to simulate some human pathology. Several studies have been already carried out on lamb fetuses using electromagnetic flowmeters placed around the cord and catheters, with pressure sensors placed inside the fetal aorta. Most of the time only the umbilical flow was assessed on the fetal side. The aim of the present work was to develop a new Doppler system able to monitor in real time and simultaneously, the fetal cerebral and the umbilical arterial flows as well as the uterine circulation. New flat Doppler probes have been designed, to be implanted on the fetus and on the mother, which makes possible the atraumatic assessment of fetal and maternal flows during approximately 20 days. The 4-MHz CW Doppler probe consists of two rectangular piezoelectric transducers of 13-mm wide, preoriented at 45 degrees from the surface of the probe, placed in a 6-mm-high plastic case in which small holes are made to sew the probe on the fetal skin. The sensors are fixed on the fetal skin, facing the umbilical cord, the fetal cerebral arteries and in front of the uterine arteries.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Feto/fisiopatologia , Ultrassonografia Pré-Natal/métodos , Animais , Velocidade do Fluxo Sanguíneo , Circulação Cerebrovascular , Feminino , Injeções Intravenosas , Modelos Biológicos , Consumo de Oxigênio , Gravidez , Ovinos , Artérias Umbilicais/diagnóstico por imagem , Artérias Umbilicais/fisiopatologia
17.
Br J Obstet Gynaecol ; 94(8): 742-5, 1987 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-3311131

RESUMO

In a series of 244 pregnancies referred for fetal echocardiography, the umbilical artery waveform was also studied by pulsed Doppler ultrasound. In 152 normal pregnancies diastolic flow in the umbilical artery was always detectable after 20 weeks gestation. In 4 of 58 normal patients examined before 20 weeks, diastolic flow was absent in some part of the recording. In 34 fetuses with congenital heart disease detected at between 18 and 37 weeks gestation, 10 were found consistently to have associated absent diastolic flow. Five of these fetuses died in utero between 5 and 21 days after the recording; three were aborted and the remaining two died in the neonatal period at 4 and 7 days after the examination. Fetal congenital heart disease with normal umbilical blood flow also had a poor prognosis in general, but the adverse outcome was much less immediate than in fetuses with absent diastolic flow. No correlation was found between the type of congenital heart disease and the characteristics of the umbilical artery waveform. Absent diastolic flow in the umbilical artery indicates a poor short-term prognosis for fetuses with congenital heart disease, particularly after 20 weeks, when fetal death is predictable.


Assuntos
Cardiopatias Congênitas/fisiopatologia , Diagnóstico Pré-Natal/métodos , Ultrassonografia , Artérias Umbilicais/fisiopatologia , Diástole , Feminino , Morte Fetal/diagnóstico , Humanos , Gravidez , Prognóstico , Fluxo Sanguíneo Regional
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