The amniotic fluid index is one of the conditions to determine whether the fetus is developing healthily in the mother’s body and to determine whether the mother can have a smooth delivery. The normal range of amniotic fluid index at 37 weeks of gestation is between 5-25 cm, less or more than this value indicates too little or too much amniotic fluid. The normal value of amniotic fluid is 300-2000 ml. The depth of amniotic fluid in the second trimester is normal between 3-7 cm. More than 7 cm is too much amniotic fluid and less than 3 cm is too little amniotic fluid. In obstetrics, the uterus is divided into 4 quadrants, marked by the umbilical level and the abdominal white line, and the sum of the vertical diameter of the largest amniotic fluid pool in each quadrant is called the amniotic fluid index. Under normal conditions, the amount of amniotic fluid in the uterine cavity varies dynamically. It usually fluctuates between 5,000 and 2,000 ml. The amount of amniotic fluid is relatively low in the early stages of pregnancy and reaches its maximum after 36 weeks of gestation. If an ultrasound is done at 37 weeks of pregnancy and the amniotic fluid index is found to be greater than or equal to 25 cm, it can be defined as excessive amniotic fluid, while an amniotic fluid index less than or equal to 5 cm is defined as too little amniotic fluid, as long as it is between 5 and 25 cm it is normal. An elevated amniotic fluid index is usually due to abnormal development of the fetal neural tube or digestive tract, and low amniotic fluid may be caused by fetal urinary tract dysplasia. Too much amniotic fluid or too little amniotic fluid is not good for the fetus. Abnormal amniotic fluid indicates the possibility of fetal abnormalities, but not necessarily abnormalities. Therefore, it is necessary to have regular amniotic fluid monitoring, but there is no need to be overly nervous. The woman’s amniotic fluid will decrease in the second trimester as the fetus grows, but as long as it is not less than three centimeters, it is within the normal range, so you should drink more water and eat more green fruits and vegetables.