Increased acidosis and hypoxaemia is seen in:
Doppler Study of Middle Cerebral Vessels:

Normally the middle cerebral vessels have high resistance flow and are characterised by little diastolic flow.
In case of IUGR a brain-sparing effect is seen with a reduction in the resistance indices in the middle cerebral vessels (i.e. increased flow) due to the shunting of blood to the brain in IUGR. Whereas in other areas (as aorta in the options) show decreased flow.
“Increased fetal diastolic flow in middle cerebral artery with absent diastolic flow in aorta implies fetal acidemia.”

Dutta Obs. 7/e, p 648
As far as persistence of diastolic notch in uterine artery is concerned, it signifies pregnancies destined to develop preeclampsia.
Normal Doppler wave form
Increased fetal diastolic flow in the middle cerebral artery with absent diastolic flow in the aorta
Presence of the 'notch' in the uterine artery
Absent umbilical artery