The presence of hydronephrosis in the fetus does not have much to do with the amount of water the mother drinks. For most fetuses, the detection of hydronephrosis is usually related to congenital ureteral anomalies, such as the presence of pyelonephrosis caused by upper ureteral stenosis. Normally, drinking water alone does not cause fetal hydronephrosis, and there is no direct relationship between the two. Fetal hydronephrosis as a congenital disease, usually after the birth of the child, timely cooperation with the doctor for treatment, can improve the symptoms of the child. However, if the symptoms of hydronephrosis are more serious and not treated in time, it may lead to loss of kidney function, and nephrectomy treatment is needed if necessary. Therefore, after a fetus develops hydronephrosis, the specific cause should be clarified, and if necessary, appropriate treatment should be given after the birth of the child to improve the child’s symptoms.