The normal range of amniotic fluid at 25 weeks of pregnancy, regardless of the number of weeks of pregnancy, the depth of amniotic fluid and amniotic fluid index should be in the normal range. From two aspects to indicate the normal amniotic fluid value, one is the depth of amniotic fluid, the other is the amniotic fluid index, the details are as follows: 1, amniotic fluid depth (AFV): ultrasound examination indicates that the vertical depth of the largest pool of amniotic fluid that is the amniotic fluid depth, the normal range is 30-80mm, the general AFV <20mm suggests that the amniotic fluid is too little, AFV>80mm suggests that the amniotic fluid is too much; 2, amniotic fluid index (AFI): The normal range is 80-250mm, generally AFI≤5mm suggests that the amniotic fluid is too little, AFI≥25mm suggests that the amniotic fluid is too much. Measurement is to pregnant women umbilical cord level and abdominal white line as a sign, the uterus is divided into four right-angled quadrants, with ultrasound measurement of the uterine quadrant of the largest amniotic fluid pool of the vertical diameter line, and then add the four vertical diameter line and the resulting sum is the amniotic fluid index. Too much or too little amniotic fluid is a pathological condition, suggesting that the mother has certain problems or the fetus has developmental abnormalities, chromosomal abnormalities may be found, once the abnormalities are found, we need to actively search for the cause of the disease, and then give targeted treatment.