Urinary tract abnormalities detected antenatally: investigations and management

Abnormalities of the urinary tract (AUTAs) are some of the commonest abnormalities detected in the foetus due to increased resolution of the ultrasound machines, detailed foetal scanning at 20 weeks of gestation and the increase in foetal medicine specialists. Even minor abnormalities can cause considerable anxiety to prospective parents and appropriate information and counselling needs to be provided. More severe abnormalities will usually be referred to specialist centres where counselling can be provided by the paediatric nephrouroradiology team. Severe oligohydramnios usually portends a poor prognosis but counselling about the foetal outcome is never dogmatic. There are few indications for antenatal intervention involving vesicoamniotic shunts. Severe abnormalities are best delivered at a centre with regional nephrourology expertise. However, most abnormalities are not severe and are unilateral with a good prognosis for long-term kidney function. There needs to be a proper mechanism for communication with neonatal staff so that severe abnormalities are referred at birth and more minor abnormalities are investigated in an appropriate manner. The natural history of many AUTAs has still not been defined and the management of conditions such as asymptomatic moderate hydronephrosis due to pelviureteric junction obstruction (or hold-up) needs to be discussed at a nephrouroradiology meeting.