<s>[INST] context: (Increased fetal diastolic flow in the middle cerebral artery with absent diastolic flow in the aorta)(648- D)Doppler - direction as well as velocity of blood flow can be measured by doppler ultrasound.* Reduced diastolic flow indicates high resistance in the downstream vessel and low tissue perfusion. Presence of'notch' in the early diastolic waveform also indicates high resistance in the downstream vessel and low tissue perfusion.* *Presence of notch in uterine artery when confirmed bilaterally at 24 weeks indicates the possible development of preclampsia and fetal growth restriction* Absent end diastolic flow in the umbilical artery was associated with 16% fetal death rate and reversed diastolic flow with 50% fetal death rates.* * Increased fetal diastolic flow in the middle cerebral artery (centralization of flow) with absent diastolic flow in the aorta implies fetal acidemia** Abnormal venous waveforms (ductus venosus, IVC) indicates fetal cardiac dysfunction (failure)Single umbilical artery - It is more common in twins and in babies bom of diabetic mothers or in polyhydramnios.* It is frequently associated with congenital malformation of the fetus (10-20%). Renal and genital anomalies, Trisomy 18 are common, (228-D)* There is increased chances of abortion, prematurity, IUGR, and increased perinatal mortality. [/INST] question: Increased acidosis and hypoxaemia is seen in | options: A: Normal doppler wave form B: Increased fetal diastolic flow in the middle cerebral artery with absent diastolic flow in the aorta C: Presence of the 'notch' in the uterine artery D: Absent umbilical artery | answer: B </s>