Amniotic fluid can be replenished with about 2000ml of water several times a day, including fluid such as soy milk, but this method is only applicable to cases where the amount of amniotic fluid is low due to insufficient fluid intake. When the mother is dehydrated and her blood volume is insufficient due to a certain disease, the plasma osmolality of the pregnant woman increases, which leads to a corresponding increase in the plasma osmolality of the fetus and a decrease in the formation of urine, which leads to a decrease in the amount of amniotic fluid. Low amniotic fluid refers to the amount of amniotic fluid less than 300ml in late pregnancy, which is mainly related to the decrease of amniotic fluid production or the increase of amniotic fluid leakage, and the common causes are mainly fetal structural abnormalities, placental hypoplasia, amniotic membrane lesions, etc. Therefore, low amniotic fluid is often associated with fetal growth restriction and even intrauterine death. When the amniotic fluid volume is repeatedly low, the most important thing is to screen for the cause of low amniotic fluid and monitor the fetal growth and development. If the pregnancy is full term and the fetus is viable outside the uterus, the pregnancy should be terminated promptly. In cases of placental dysfunction or low amniotic fluid at the time of rupture of membranes, the pregnancy should be terminated by cesarean section if the delivery cannot be ended in a short time. For those whose pregnancy is not full term and whose fetal lungs are immature, treatment can be tailored to the cause, prolong the gestational week as much as possible, and terminate the pregnancy if necessary according to the gestational age and intrauterine condition of the fetus.