The depth of amniotic fluid is usually normal from 20 to 80mm. When the depth of amniotic fluid is >80mm, excessive amniotic fluid is considered, which may be caused by fetal structural abnormalities, pregnancy comorbidities and complications. When the depth of amniotic fluid is <20mm, consider too little amniotic fluid, which is mainly related to the decrease of amniotic fluid production or the increase of amniotic fluid leakage. Amniotic fluid has the role of protecting the fetus and protecting the mother, and it is important to closely monitor the amount of amniotic fluid during pregnancy to observe any possible problems with the fetus. Conditions such as chromosomal abnormalities in the fetus can also be detected by amniocentesis. During pregnancy, you should undergo regular obstetric checkups in a regular hospital and observe the amount of amniotic fluid to detect problems and make appropriate treatment in time.