How much amniotic fluid index is considered low

Patient's question:

No

Doctor's answer:

Generally speaking, amniotic fluid depth of 3-7 cm is normal, exceeding 7 cm indicates polyhydramnios, and less than 3 cm indicates oligohydramnios. Amniotic fluid index (AFI) of 8-20 cm is considered normal amniotic fluid volume. When the AFI is less than 5 cm, it indicates oligohydramnios, and exceeding 20 cm indicates polyhydramnios.