RESUMO
OBJECTIVE: Fetal megacystis has a poor prognosis. During the first trimester, it is frequently associated with chromosomal abnormalities or multiple malformations, but can also be isolated and resolve spontaneously. In this study, our main objective was to determine the fetal and pediatric prognosis in this particular situation. METHODS: This was a retrospective multicenter study. We describe the cases referred to our fetal medicine centers and also cases previously reported in the international literature. RESULTS: Five cases were referred to our fetal medicine centers. After spontaneous resolution of megacystis, close ultrasound follow-up revealed urinary tract abnormalities in all cases. These abnormalities were all transient. After birth, 1 of the children developed a mild ureteropelvic junction obstruction. Pediatric follow-up was normal for the other children. Our 5 cases plus 79 in the literature mean that 84 cases of isolated first-trimester fetal megacystis with spontaneous resolution have been reported to date. The risk of chromosomal abnormality was 2.4% (2/84) and pediatric follow-up was normal in 96.4% of cases (81/84). CONCLUSION: Even when isolated first-trimester fetal megacystis resolves spontaneously, fetal karyotype analysis and close prenatal ultrasound follow-up should be performed. When there is no chromosomal abnormality, the renal pediatric prognosis seems to be good.