Fetal megacystis across the gestational ages: The same sign for varying etiologies and outcomes.

Objective: To compare the etiologies and perinatal outcomes of fetal megacystis according to their gestational age at diagnosis. The second aim is to detect the prognostic sonographic criteria in each gestational age group. Methods: Fetal megacystis cases detected over eight years were retrospectively searched on hospital records. They were classified into three groups according to the gestational age at diagnosis: first, second, and third trimester of pregnancy. Pregnancy outcomes, postnatal prognosis, and etiologies were compared between the groups. The sonographic criteria that predicted the adverse outcomes were assessed for each trimester. Results: A total of seventy-eight cases of fetal megacystis were included in the study. Thirty-two, forty, and six of the cases were diagnosed in the first, second, and third trimester respectively. 38.4% of the fetuses were born alive, and 19.2% of the fetuses survived beyond infancy. Gestational age at diagnosis, the presence of signs of renal impairment, and increased bladder diameter were associated with poor outcomes in the first trimester. Oligohydramnios, earlier gestational weeks at diagnosis, and an increased bladder length/biparietal diameter ratio were associated with poor outcomes in the second trimester. Third-trimester cases had better outcomes and were associated with varying pathologies. Conclusion: The underlying etiologies of megacystis vary depending on gestational age at diagnosis. It may have a favorable prognosis when it presents in the later gestational ages and when abnormal amniotic fluid volume does not accompany. LBD: BPD ratio higher than 0.96 can be used as a poor prognostic factor in the second trimester of pregnancy. [ABSTRACT FROM AUTHOR]