Fetal renal blood flow velocimetry and cerebro-placental ratio in patients with isolated oligohydramnios.

Objective: It's proposed that oligohydramnios is caused by decreased renal perfusion due to redistribution of fetal blood at fetal growth restriction. Isolated oligohydramnios refers to the presence of oligohydramnios without fetal structural and chromosomal abnormalities, without fetal growth restriction, without intrauterine infection, and in the absence of known maternal disease. It's unknown whether the redistribution or decreased renal perfusion cause isolated oligohydramnios.