To investigate the value of prenatal ultrasound in diagnosis of fetal posterior urethral valve (PUV) and the differential diagnosis of related diseases.

The antenatal ultrasonographic manifestations and the outcomes of 14 cases with congenital lower urinary tract obstruction (LUTO) in Shengjing Hospital of China Medical University from December 2014 to December 2016 were analyzed. The ultrasound features and differential diagnosis of fetal posterior urethral valve were summarized and analyzed.

Fourteen male fetuses with LUTO were prenatally diagnosed. Eleven fetuses were diagnosed as PUV, 1 as urethral atresia, 2 as megacystis and LUTO. Among the fourteen fetuses, 11 were confirmed as PUV after delivery, 1 as urethral atresia, 2 as vesicoureteral reflux (VUR). One case among them was diagnosed as PUV, and latter proved to be VUR. In 2 cases among them, prenatal ultrasound indicated megacystis, but 1 case was proved to be PUV, and 1 case was VUR. The prenatal ultrasound of the PUV fetuses showed enlarged bladder and thickened bladder wall. Most of them were accompanied by the keyhole sign.

Prenatal ultrasound can assist in the diagnosis of PUV by analyzing the anatomy of the bladder and accompanying malformations, which provides valuable diagnostic information for the clinical practice.