[Fetal anteroposterior renal pelvic diameter for predicting antenatal hydronephrosis requiring postnatal surgery]

To assess the value of fetal anteroposterior renal pelvic diameter (APD) in predicting antenatal hydronephrosis requiring surgical treatment after birth.

A total of 525 cases of antenatal hydronephrosis detected by prenatal ultrasonography (ultrasound index APD ≥ 4 mm in the second trimester and APD ≥ 7 mm in the third trimester) in Zhejiang Prenatal Diagnosis Center from June 2007 to June 2018 were retrospectively analyzed. ROC curve was used to analyze the relationship between these ultrasound indicators and the requirement for surgical treatment after birth.

There were 162 cases (30.9%) diagnosed in the second trimester and 363 cases (69.1%) diagnosed in the third trimester; 131 cases were diagnosed pathologically after birth, of which 121 finally underwent surgical treatment. The area under ROC curve (AUC) of APD in middle pregnancy for prediction of requiring surgery 1-12 years after birth was 0.910; the cut-off value of APD was 8.45 mm with a sensitivity of 97.1%, specificity of 70.9%, positive predictive value (PPV) of 47.9%, and negative predictive value (NPV) of 98.9%. The AUC of APD in late pregnancy for prediction of requiring surgery 1-12 years after birth was 0.800; the cut-off value of APD was 12.25 mm with a sensitivity of 66.7%, specificity of 81.2%, PPV of 51.7%, and NPV of 89.1%.

APD in pregnancy can be used to predict whether the fetus with hydronephrosis needs surgical treatment after birth, and the prediction value of APD in the middle pregnancy is better.