OBJECTIVE: To estimate the effect of prenatal bladder drainage on perinatal survival in fetuses with lower urinary tract obstruction. DATA SOURCES: Relevant articles were identified by searching the databases MEDLINE (1966-2002), EMBASE (1988-2002), and the Cochrane library (2000;4). METHODS OF STUDY SELECTION: Studies were selected if the effect of prenatal bladder drainage (vesicocentesis, vesicoamniotic shunt, or open fetal bladder surgery) on perinatal survival was reported in fetuses with ultrasonic evidence of lower urinary tract obstruction. Study selection, quality assessment, and data abstraction were performed independently and in duplicate. TABULATION, INTEGRATION, AND RESULTS: Sixteen observational studies that included nine case series (147 fetuses) and seven controlled series (195 fetuses) were identified. Study characteristics and quality were recorded for each study. Data on the effect of bladder drainage on perinatal survival were abstracted. Where controlled data were available, 2 x 2 tables were generated to compare the effects of bladder drainage versus no bladder drainage on perinatal survival. Pooled odds ratios (ORs) were used as summary measures of effect, and the results were stratified according to predicted fetal prognoses (based on ultrasound features and fetal urinary electrolytes). Among controlled studies, bladder drainage appeared to improve perinatal survival relative to no drainage (OR 2.5; 95% confidence interval [CI] 1.1, 5.9; P =.03). However, this observation was largely because among the subgroup of fetuses with a poor prognosis there was a marked improvement (OR 8.1; 95% CI 1.2, 52.9; P =.03). Improved perinatal outcome was also suggested in those fetuses considered to have a good prognosis (OR 2.8; 95% CI 0.7, 10.8; P =.13). CONCLUSION: There is a lack of high quality evidence to reliably inform clinical practice regarding prenatal bladder drainage in fetuses with ultrasonic evidence of lower urinary tract obstruction. The limited available evidence suggests that prenatal bladder drainage may improve perinatal survival in these fetuses, particularly those with poor predicted prognoses. Further research in the form of a multicenter randomized controlled trial is required to assess the short- and long-term effects of this intervention.