There are two clinical methods of measuring and assessing amniotic fluid volume, including amniotic fluid index and amniotic fluid depth, the latter of which is determined by measuring the maximum anterior and posterior diameters of the largest dark area of amniotic fluid in the uterine cavity. The amniotic fluid depth, which is normally 3-8 cm, or the maximum anterior-posterior diameter of the amniotic fluid, is an important indicator for assessing the amount of amniotic fluid in the middle and late stages of pregnancy. When the maximum depth of amniotic fluid, that is, the maximum anterior-posterior diameter of amniotic fluid, exceeds 8cm, it is called excessive amniotic fluid, which is mainly caused by gestational diabetes mellitus, twins or multiple births, fetal malformation, and may present with symptoms such as abdominal distension, dyspepsia, diaphragm rising, heart shifting, lower limb edema, varicose veins, and so on. In the case of excessive amniotic fluid, the pregnant woman is required to eat a low-salt diet and undergo an ultrasound to check the condition of the fetus, so as to determine whether there are any malformations or hereditary diseases. If there is no abnormality in the fetus, the amniotic fluid is too much and the pregnant woman is bloated and uncomfortable, amniocentesis can be used to decompress the amniotic fluid to relieve the excessive tension caused by the excessive amniotic fluid, alleviate the symptoms, and prolong the duration of the pregnancy. When the maximum depth of amniotic fluid, that is, the maximum anterior-posterior diameter of amniotic fluid, is lower than 2cm, it is called amniotic fluid hyponatremia, which is mainly due to the decrease of amniotic fluid production, the increase of absorption and leakage, and it will appear that the fetal movement is obvious and accompanied by abdominal pain when the fetus moves. When the test result suggests that the amniotic fluid is too low and the fetus is normal, it is necessary to analyze it according to the development of the fetus and give corresponding treatment. Low amniotic fluid is also prone to be combined with fetal malformations and close monitoring is recommended.