Surveillance of twin pregnancy with umbilical arterial velocimetry

Umbilical blood waveforms in fetal surveillance of twins

Umbilical arterial velocity waveforms were recorded in 69 pairs of twins by means of continuous-wave Doppler analysis and an Angioscan spectrum analyzer. A systolic/diastolic ratio was measured for each twin. The sum of the systolic/diastolic ratio was calculated and the difference between each twin was expressed as the delta systolic/diastolic ratio. Significant differences in delta systolic/diastolic and neonatal weight were previously set at 0.4 and 350 gm, respectively. Sonography was used for fetal age confirmation and diagnosis of fetal growth retardation. All neonates were weighed; at birth gestational age was assigned by Dubowitz criteria and categorized as adequate-, small-, or large-for-gestational age. The sensitivity, specificity, and predictive value of the delta systolic/diastolic ratio were determined. The perinatal implications of this test in the management of twin pregnancy are discussed.

The clinical implications of Doppler ultrasound analysis of the uterine and umbilical arteries

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

Timely diagnosis by cardiotocography of critical fetal reserve due to fetofetal transfusion syndrome

In a review of 90 twin pregnancies monitored by antenatal cardiotocography there were 8 cases of subsequently proven fetofetal transfusion syndrome. In 2 of these evidence of severe fetal stress had indicated immediate delivery; the 4 babies survived in circumstances that were perilous. In 1 case there was no evidence of critical fetal reserve but the recipient twin died, this probably representing an acute fetofetal transfusion during labour. In the 5 milder cases with no evidence of stress on cardiotocography, all babies survived and they required minimal or no treatment for problems relating to the fetofetal transfusion. In multiple pregnancy the cardiotocograph offers the additional bonus of detection of fetal compromise due to fetofetal transfusion.

Uterine artery Doppler velocimetry in pregnant women with hypertension

Uterine and umbilical artery velocimetry was carried out on 71 women with hypertensive disorders in pregnancy. Three categories of hypertensive disease were diagnosed: chronic hypertension, preeclampsia, and chronic hypertension with superimposed preeclampsia. Clinical classifications describe the severity of disease effectively, primarily because the classification is based on the appearance of abnormal physical or laboratory findings. Doppler velocimetry of the uterine arteries shows that normal pregnancy occurs when the systolic/diastolic ratio is less than or equal to 2.6. When the ratio exceeds this level and there is a notch in the waveform, the pregnancy is complicated by stillbirth, premature birth, intrauterine growth retardation, and maternal preeclampsia. The positive and negative predictive value of the examination is 93% and 91%, respectively. It appears that this new technology will be an essential ingredient of optimum pregnancy surveillance.