Placental insufficiency (aka utero-placental insufficiency) is insufficient blood flow to the placenta during pregnancy. It is also used to designate late decelerations of fetal HR as measured by electronic monitoring, even if there is no other evidence of reduced blood flow to the placenta, normal uterine blood flow rate being 600mL/min.

Although not necessarily causes, as it can occur in normal healthy placentas and full term healthy births, it includes:

• Abnormally thin placenta, <1cm
• Circumvallate placenta
• Amnion cell metaplasia, amnion nodosum
• Increased syncytial knots
• Calcifications
• Infarcts due to focal or diffuse thickening of blood vessels
• Villi capillaries occupying about 50% of the villi volume, or when <40% of capillaries are on the villous periphery

• CTG, showing late decelerations of FHR
• Fetal movement counting
• U/S
• AFI

• Delivery

• The various investigations have been promoted as supposedly diagnostic of placental insufficiency, but have been unsuccessful at predicting stillbirth

• CTG
• Placental abruption (placenta separates off the uterine wall, causing NO blood flow to the placenta, causing immediate fetal demise)