Fetal medicine





Percutaneous shunting for fetal Lower Urinary Tract Obstruction

Go to the PLUTO study website


Congenital fetal lower urinary tract obstruction (LUTO) is usually identifiable using ultrasound.  Its natural history is associated with a high prevalence of chronic renal impairment in infancy and childhood. If associated with oligohydramnios of early-onset there is a significant risk of pulmonary hypoplasia, with perinatal mortality within the early neonatal period. Even if oligohydramnios has not yet developed, there is a significant risk of renal impairment, secondary to obstruction.  In utero, percutaneous vesicoamniotic shunting bypasses the congenital urethral obstruction to potentially improve fetal outcome.  To date, there are no large prospective studies assessing the risks and benefits of this intervention to either mother or baby.


Study design

Multi-centre randomised controlled (RCT) trial of 150 singleton pregnancies with ultrasound evidence of LUTO to evaluate the safety and effectiveness of in utero shunting compared to conservative management. Babies who survive will also be followed up for effects upon renal and bladder function and cognitive development. This trial will provide important information to guide future clinical practice and research.  In addition, it will provide information to counsel women whose babies have prenatally diagnosed bladder outflow obstruction.

Those pregnancies not entered into the RCT PLUTO trial, are entered onto a register, so that outcome may be tracked.

Eligibility for the RCT will primarily be based on the “Uncertainty Principle”.  This is that if the fetal medicine specialist is uncertain as to whether shunting is the most appropriate option, then the pregnancy (and fetus) is eligible to be randomised. The minority of pregnancies where the clinician is certain that ‘shunting’ is clinically indicated or contraindicated or where the women declines randomisation will be entered on to a prospective registry. Data from trial and registry babies will used to construct a prognostic risk index.


Study population

- Inclusion criteria: All lower urinary tract obstructions with normal male karyotype

- Exclusion criteria: Other structural malformations, female or abnormal karyotype, multiple pregnancies, language problems for informed consent.


Vesicoamniotic shunt placement will be compared with conservative management.


Outcome measures

The aim of the study is to investigate the benefit of vesicoamniotic shunt placement compared to conservative management. The primary outcome measure is to determine if intrauterine vesicoamniotic shunting for fetal bladder outflow obstruction, compared to conservative, non-interventional care improves perinatal and neonatal morbidity and mortality and renal function. Secondary outcome measure is to determine the long-term effects of shunt placement.

Power/data analysis

The sample size of 150 patients will allow reliable (80% power á=0.003) detection of a 23% improvement in survival (i.e. 50% improved to 73%). Analyses will be undertaken using a chi-squared test to examine survival proportions and multi-level modelling techniques for any continuous repeated measurements, i.e. creatinine clearance levels.


Time schedule

Inclusion period will last until 2013.


M. Kilby, Brimingham Women’s Hospital, United Kingdom

D. Oepkes, LUMC, Leiden University Medical Centre, the Netherlands

P.N. Adama van Scheltema, LUMC, Leiden University Medical Centre, the Netherlands