The normal range of amniotic pool depth is 20 to 80 mm. The depth of the amniotic pool is the vertical depth of the largest amniotic pool and is an important indicator of how much amniotic fluid is present as measured by ultrasound. Normal amniotic fluid depth is between 20 and 80mm, >80mm is too much amniotic fluid, <20mm is too little amniotic fluid. It can also be judged by the amniotic fluid index, which is the sum of the depth of amniotic fluid in the four quadrants of the uterus measured by ultrasound, and is considered to be normal from 50 to 250 mm. Specific to each gestational week for the statistical data of the mean plus or minus the standard deviation, not a mean value, for ordinary control is not significant. Excessive amniotic fluid is common in hypertensive syndromes of pregnancy, fetal malformations, twin pregnancies, and diabetic patients. Early amniotic fluid is often combined with fetal malformations, most commonly renal insufficiency. Hyponatremia is often associated with term pregnancies. To summarize, too much or too little amniotic fluid is an abnormality, and the depth of amniotic fluid on ultrasound varies from week to week. You should pay attention to regular pregnancy checkups, and if you find amniotic fluid abnormalities, you should consult a doctor in time and actively diagnose and treat them.