The depth of amniotic fluid during pregnancy, the normal range is generally 2cm~8cm. In general, the depth of amniotic fluid during pregnancy is the vertical depth of the darkest area of the amniotic fluid, and the normal range is 2cm~8cm. ≥8cm is called too much amniotic fluid, and ≤2cm is too little amniotic fluid. Excessive amniotic fluid or too little amniotic fluid are both considered abnormal and the cause should be further investigated. Abnormalities in placental function may also lead to oligohydramnios if the fetus has decreased urination and amniotic fluid, whereas excess amniotic fluid may be associated with open neural tube malformations and gastrointestinal obstruction in the fetus. To summarize, the depth of amniotic fluid during pregnancy, the general normal range of 2cm ~ 8cm; if the amniotic fluid or amniotic fluid is too much or too little should be timely consultation, by the doctor to clarify the cause, give targeted treatment.