Relevance of Doppler studies in prediction of progressive foetal hypoxia but not acidaemiaia.

How much relevant is  venous  Doppler of Umb venous flow ? :à Yes. The abnormal venous Doppler parameters, including that of Umb veins  are the strongest Doppler predictors of stillbirth. Reasons are even among fetuses with severe arterial Doppler abnormalities the risk of stillbirth is largely confined only to those fetuses that haves abnormal venous Doppler’s. But Venous Doppler findings of DV that are particularly ominous are 1) absence or 2) reversal of the ductus venous 3) “ a”  wave and  & 4)  biphasic /triphasic umbilical venous pulsations. In such settings there is a risk of a 25% stillbirth. But when the study is limited to preterm severe IUGR population these Doppler findings have a 65% predictive sensitivity and 95% specificity, when fetal compromise is  accelerated there is a further steady rise in umbilical blood flow resistance venous Doppler indices escalate  over a wide range and the development of Oligohydramnios and metabolic academia is characteristics of  ineffective downstream delivery of cardiac dilatation with hole systolic tricuspid insufficiency complete fetal inactivity , short term variation below 3.5 msec and spontaneous cardiac late decelerations of the fetal heart rate can be observed as preterminal events.

How placental dysfunction is is reflected in Doppler indices?? Ans:- As diagnostic tools 1) elevated umbilical artery blood flow resistance 2) and /or middle cerebral artery brain sparing provide evidence of placental dysfunction.

In the fetal compartment elevation of the umbilical artery Doppler index is observed when approximately 30% of the fetal villous vessels are abnormal.

What does “Absence or even reversal of umbilical artery end diastolic velocity: warns us in an whispering voice?? Ans:- Such changes may  occur when 60% to 70% of the villous vascular tree is damaged. Therefore, the benefit of umbilical artery Doppler , umbilical artery Doppler , when used in conjunction with standard antepartum testing was associated with a decrease  of up to 38% in perinatal mortality antenatal admissions, inductions of labor and cesarean deliveries for fetal distress in labor in women considered at high risk.

What other in formations we receive from Umbilical vessels??  Ans:-Development of umbilical venous pulsations in fetuses with absent end diastolic velocities in the umbilical artery was associated with a fivefold increase in mortality. Researchers have demonstrated that gestational age at  the onset maternal hypertension and the development of pulsations in the umbilical venous velocities were significantly correlated with the interval of time between diagnosis and delivery for late decelerations for the FHR.