Severe Fetal Megacystis - The Real Story

Abstract

Purpose To investigate the prognostic factors, fetal survival and outcomes for fetuses with severe megacystis. Material and Methods 60 consecutive cases of antenatally diagnosed severe megacystis between 1988 to 2008 were reviewed from a statewide tertiary referral centre for major fetal abnormalities. Normal fetal bladder sagittal length (FBSL) was represented by the approximate linear formula: FBSL=gestational age (GA) in weeks –5. The relative bladder size (as a percentage of normal for that GA) was compared between the survivor group (n=14) and the fetal/neonatal death group (n=17). All terminations were excluded. Results Mean GA at diagnosis was 18.0 weeks (range 11 to 39). In males megacystis was secondary to posterior urethral valves in 33% (n=17), prune belly syndrome in 22% (n=11) and prostatic hypoplasia/atresia in 20% (n=10). Urethral stenosis (n=3), and 1 case each of prune belly, megacystis-microcolon-intestinal hypoperistalsis syndrome, pelvi-ureteric junction obstruction, urethral diverticulum, and urethral ‘S’ band were identified in the 9 female fetuses. The relative bladder sizes of the two groups were similar: survivor group 310.2±108% vs. fetal/neonatal death group 309.8±120%. Fetuses with megacystis and oligohydramnios had an increased risk of death compared to those who had megacystis without oligohydramnios (OR=11.7; 95%CI 2.1– 64.0, p=0.028). The 14 survivors are aged between 4 months and 18 years old. Table 1 . Outcomes of 60 fetuses with severe megacystis Male (n=51) Female (n=9) Terminated 20 7 Vesicocentesis/fetal urinalysis 24 0 Vesicoamniotic shunt 2 0 Cystoscopic laser ablation 4 0 Fetal/neonatal death 16 1 Alive 13 1 Loss to follow-up 2 0 Conclusions Severe megacystis is a serious fetal condition with a wide variety of diagnoses. Mortality is high with or without intervention. Relative bladder size alone does not predict survival. Fetuses with severe megacystis and normal AFI have a higher survival rate.