RESUMO
Qualitative analysis of blood velocity in the umbilical arteries of twin fetuses detected by pulsed Doppler ultrasound revealed discordant patterns which permitted an accurate antenatal diagnosis of an artery-to-artery anastomosis. One twin was consistently larger than the other, had a normal umbilical artery impedance and survived; the other fetus was consistently smaller, had persistently high umbilical artery impedance and died in utero. The death of one fetus did not affect the blood flow patterns within the umbilical artery of the other up to delivery 24 h later. The case demonstrates that intrauterine morbidity due to vascular anastomoses is not confined to the transfusion of significant amounts of blood from one fetus to another.
Assuntos
Fístula Artério-Arterial/congênito , Doenças em Gêmeos , Diagnóstico Pré-Natal/métodos , Ultrassonografia , Artérias Umbilicais , Adulto , Fístula Artério-Arterial/diagnóstico , Feminino , Morte Fetal , Humanos , GravidezRESUMO
An unexplained intrauterine death occurred within 12 hours of a normal reactive nonstress test. Furthermore the umbilical arterial impedance measured by pulsed Doppler ultrasound was also normal.
Assuntos
Morte Fetal/diagnóstico , Coração Fetal/fisiologia , Monitorização Fetal/métodos , Ultrassonografia , Adulto , Velocidade do Fluxo Sanguíneo , Feminino , Frequência Cardíaca , Humanos , Idade Materna , Gravidez , Gravidez de Alto Risco , Fluxo Sanguíneo Regional , Ultrassom , Artérias Umbilicais/fisiologiaRESUMO
A Doppler ultrasound technique was used to measure the effect on human umbilical artery impedance of a single moderate dose of alcohol consumed by mothers compared to a control solution in six normal third-trimester pregnancies. No significant difference in impedance was detected between the alcohol and the control solutions during the subsequent 90 minutes. The results suggest that the known toxicity of maternally ingested alcohol is probably mediated by some mechanism other than a significant acute alteration in fetoplacental blood flow characteristics.
Assuntos
Etanol/farmacologia , Troca Materno-Fetal/efeitos dos fármacos , Artérias Umbilicais/fisiologia , Velocidade do Fluxo Sanguíneo , Etanol/toxicidade , Feminino , Humanos , Gravidez , Fluxo Sanguíneo Regional/efeitos dos fármacos , Reologia , Artérias Umbilicais/efeitos dos fármacosRESUMO
Blood flow in the descending human fetal aorta and in the intra-abdominal portion of the umbilical vein was quantified using pulsed Doppler ultrasound in a longitudinal series of normal pregnancies, the accuracy of the method having been verified in vitro. The results obtained are in keeping with previous studies but indicate that, although the method is relatively simple, determination of absolute blood flow in these vessels has little clinical potential because of inherent measurement inaccuracies.
Assuntos
Sangue Fetal/fisiologia , Ultrassom , Aorta Torácica/embriologia , Velocidade do Fluxo Sanguíneo , Feminino , Idade Gestacional , Humanos , Gravidez , Veias UmbilicaisRESUMO
Time-velocity waveforms or sonograms obtained by pulsed Doppler ultrasound from the umbilical artery were analysed in a longitudinal study of 15 normal pregnancies. The sonograms from nine fetuses with intrauterine growth retardation were compared qualitatively and had quite different characteristics implying a high distal impedance to blood flow. Methods of analysis capable of differentiating between the normal and abnormal sonograms are described and discussed.
