Hospitalization for low amniotic fluid needs to be based on the presence or absence of fetal malformations and the size of the gestational week to choose the treatment plan. 1. Hyponatremia combined with severe lethal structural anomalies: The diagnosis of severe lethal structural anomalies should be terminated as soon as possible. Ultrasound can clarify the structural anomalies of the fetus, and chromosomal abnormality testing can be relied on for interventional prenatal diagnosis, and the results of which can be evaluated and communicated to the pregnant woman and her family, and the fetus can be terminated if it is not viable. 2. Hyponatremia combined with normal fetus: find and remove the cause of the disease, and dynamically monitor the intrauterine condition of the fetus, including counting fetal movements, fetal biophysical scoring, ultrasonographic monitoring of the amniotic fluid volume and umbilical artery S/D, etc.. If the pregnancy is full-term and the fetus can survive outside the uterus, timely termination of pregnancy can be considered. If the pregnancy is not full-term, actively treat the etiology of the disease, improve the function of the placenta, and try to prolong the gestational weeks, and the amniotic fluid volume can be improved by infusion and amniotic cavity perfusion. The detection of low amniotic fluid during pregnancy should be promptly consulted to avoid adverse events.