An amniotic fluid index of 80mm at 37 weeks of pregnancy is normal. At 37 weeks of pregnancy, amniotic fluid within 300ml to 2000ml is within the normal range. Checking the amount of amniotic fluid during pregnancy is usually done by ultrasonography, which mainly checks the vertical depth of the dark zone of maximum amniotic fluid and the amniotic fluid index, two indicators. When the amniotic fluid is normal, the depth of amniotic fluid is about 20-80mm, and the normal range of amniotic fluid index is 50-200mm. Checking the condition of amniotic fluid can determine the development of the fetus in the uterus. If the amniotic fluid is too much or too little, it is likely that there are fetal malformations, abnormal placental function, amniotic membrane lesions and other abnormalities, pregnant women need to consult a doctor in time for examination, to clarify the causes of amniotic fluid abnormalities, and to deal with them under the guidance of the doctor. Pregnant women should pay attention to regular obstetric examination during pregnancy to check the development of the fetus, if there is any abnormality, it can be dealt with in time to prevent adverse pregnancy outcomes.