Doppler of Cerbroplacental Ratio

The gaining  popularity of Doppler studies in antenatal foetal surveillance :-?? . Doppler informations   play an important role in the surveillance of uncomplicated prolonged pregnancies. The most common reason given for routine labor induction is that current fetal surveillance tests cannot accurately identify which pregnancies are at risk for an adverse outcome. Many, therefore recommend that further newer tets of antenatal surveillance are necessary which are more accurate to assess the effectiveness of the antenatal fetal testing..

A) How informative is Umbilical artery Doppler?? Ans:-Most authors have shown that increase in fetal umbilical resistance index in prolonged pregnancies is related to an increase in the adverse perinatal outcome. Buy many don’t agree and their argument is that placental aging is  not related to an increase in the resistance of the fetal umbilical artery (UA) and that most prolonged pregnancies with adverse outcome had normal umbilical artery resistance values.

2. Middle cerebral artery (MCA) resistance is known to A) decrease at the end of pregnancy. This may represent a physiological change associated with an increase in cerebral metabolic requirements, --a brain‐sparing effect to protect intracranial structures during labor  or secondary to a mild degree of placental insufficiency.

A ratio of MCA to UA, the cerebroplacental ratio (CPR), has been proposed as a better predictor of fetal compromise than either vessel considered alone, even when umbilical resistance index is within normal range. This is thought to be because the CPR evaluates the fetal hemodynamics and quantifies redistribution of cardiac output better than the umbilical or the cerebral flow alone. The good sign is :- Reference ranges for umbilical and middle cerebral artery pulsatility index and cerebroplacental ratio in prolonged pregnancies. To construct normal ranges for umbilical artery pulsatility index (UA PI), middle cerebral artery pulsatility index (MCA PI) and cerebroplacental ratio (CPR) in prolonged pregnancies according to strict methodological criteria using polynomialàThe cerebro-umbilical (MCA PI/UA PI) and cerebro-uterine (MCA PI/Uterine artery PI) ratios were calculated. Both the cerebro-umbilical are cerebro-uterine ratios were found to be higher in female fetuses (1.74 vs. 1.81 and 1.95 vs. 2.1 respectively) but this difference did not reach statistical significance (p = 0.10 and 0.09 respectively).

Bad Signs are of MCA PSV-à:- at MCA/ PI it's 0.78,,Below 5 th centile for gestational age. But there is increase in MCA-PI before fetal demise. That means cerebral circulation is adapting to deoxygenating.. This pattern was independent of Umbilical Artery blood flow. None of these fetuses died. An increase in MCA-PI before fetal demise have been used to support possible intervention. But this statement is not true in very preterm foetus when these statements don’t hold good. in very preterm fetuses with SGR.. .

. Nomograms for UA and MCA pulsatility.Doppler examinations were performed by two examiners. For each examination, the mean value of three clear consecutive waveforms was recorded. 1) UA PI obtained from a free loop of the umbilical cord; (2) MCA PI measured in the straight portion of the artery avoiding head compression by the transducer and (3) the CPR was derived as a simple ratio of the MCA PI divided by the UA PI.