Placental insufficiency (or uteroplacental vascular insufficiency) is a complication of pregnancy when the placenta is unable to deliver an adequate supply of nutrients and oxygen to the fetus, and, thus, cannot fully support the developing baby. Placental insufficiency occurs when the placenta either does not develop properly or because it has been damaged. It is commonly defined as a reduction in the maternal blood supply (reduced uterine artery blood flow). However, we define placental insufficiency to include reduction in maternal blood supply AND/OR the failure of the maternal blood supply to increase or adapt appropriately by mid-pregnancy. Placental insufficiency can result pregnancy complications, including fetal growth restriction, pre-eclampsia and others, all of which are described below. The management of placental insufficiency is dependent upon additional tests and the unique characteristics of each patient. Factors considered during management of complicated pregnancies are maternal medical and obstetrical history, weight, ethnicity, and blood pressure.