What is fetal hydronephrosis?

If the fetus has bilateral hydronephrosis, observe and analyze the amount of hydronephrosis. If the amount of hydronephrosis is less than 1cm, it belongs to normal physiological phenomenon, which may be the performance of fetal urine retention bladder filling. If the amount of hydronephrosis exceeds 1cm, it may be considered as urinary system abnormality, and further examination is recommended.