Fetal bladder catheterization in severe obstructive uropathy before the 24th week of pregnancy.

OBJECTIVE

Fetal obstructive uropathy is simple to diagnose before the 24th week of life. Drainage of the pathologically enlarged fetal bladder avoids development of hydronephrosis and destruction of kidneys and, obviously, prevents development of secondary oligohydramnios and pulmonary hypoplasia. The aim of our study was to evaluate the usefulness of a fetal bladder shunt in cases of obstructive uropathy before the 24th week of gestation.

METHODS

From January 1997 we diagnosed 6 cases of fetal obstructive uropathy before the 24th week of gestation. In all cases oligohydramnios or ahydramnios was also observed. After evaluation of the renal function on the basis of fetal urine samples, we shunted 5 fetuses. After routine preparation of the operative field, a special puncture needle was inserted through the abdominal wall of mother and fetus into the fetal bladder. Through the needle a fetal bladder catheter was inserted between the fetal bladder and the amniotic sac. After shunt placement, fetal urine fills the amniotic sac and the fetal bladder is decompressed. After the procedure, the patients were hospitalized and serial sonographic examinations were performed to evaluate shunt function. Bladder size, presence and size of hydronephrosis, and volume of amniotic fluid were evaluated.

RESULTS

The Rocket Medical catheters have an excellent 'shape memory'. All but 1 newborns had a good perinatal outcome. Mean Apgar score was 8 at 1 min, weight at delivery was between 1,700 and 3,100 g. No pulmonary hypoplasia was observed. All deliveries were after the 33rd week of gestation (range 33-38 weeks). The minimum drainage time was 11 weeks, maximum 18 weeks. In 2 cases premature delivery occurred because of premature rupture of the membranes. One newborn died of respiratory distress syndrome.

CONCLUSIONS

Early bladder drainage (before the 24th week of gestation) enables delivery of newborns with a good perinatal outcome, without pulmonary hypoplasia. This method of therapy limits renal damage and allows time for normal development of the fetal lungs.