Abstract: Objective：To evaluate the pregnancy outcome and prognosis of fetuses with hydronephrosis by ultrasonography，then to provide help for clinical intervention.Methods：Totally 124 fetuses(140 kidneys) with hydronephrosis received ultrasonography at pregnancy period.They were divided into five groups，gradeⅠ，Ⅱ，Ⅲ，Ⅳ and Ⅴaccording to the renal pelvis anteroposterior diameter(APD)，morphology of renal calyces and renal parenchyma thickness.Pregnancy outcome were followed up.Results：(1) The rate of induced labor in gradeⅠ，Ⅱ，Ⅲ，Ⅳ and Ⅴ group was3.45%，11.75%，26.32%，75.00% and 100.00%(χ2=51.062，P=0.000)，respectively.(2) Among the normal birth fetasus，in gradeⅠ，Ⅱ，Ⅲ，Ⅳ group，the prenatal improvement rate was 87.69%，69.44%，46.67% and 0.00%，the postpartum improvement rate was 12.31%，25.00%，33.33% and 50.00%，and the rate of operation treatment was 0.00%，5.56%，20.00% and 50.00%，respectively(χ2=23.382，P=0.000).Conclusion：The prenatal ultrasonography is of great value in judging the pregnancy outcome and prognosis of fetuses with hydronephrosis.

Key words: Hydronephrosis, diagnosis, Ultrasonography, Prognosis, Fetus