First trimester shunting for fetal megacystis (IUS1st) – Initial results of an ongoing prospective trial

Background Early fetal megacystis is associated with high perinatal mortality and morbidity due to pulmonary hypoplasia and renal failure. Early vesico-amniotic shunting (VAS) can preserve renal function as we could show in 2 own retrospective studies. Here we present the initial results of the prospective IUS 1^st trial (IntraUterine Shunting in the 1^st trimester) that analyzes the long term follow-up, focusing on nephrological outcome.

Material and Methods Prospective analysis of VAS for fetal megacystis>15 mm diagnosed before 14.0 weeks and treated prior to 15.0 weeks gestation using the Somatex Shunt. Pregnancy course, complications and perinatal outcome were analyzed. Nadir creatinine in the first week, first month and first year of life were monitored.

Results VAS was performed in 27 fetuses at a mean gestational age of 13.5 weeks (range 11.6-14.5). The mean bladder diameter was 31mm (range 16-46). One shunt was initially misplaced and needed reintervention the following day, all other interventions were successful. In 4 cases, we observed shunt dislocation in the subsequent course of pregnancy. 17 children were born alive at a mean gestational age of 37.5 weeks (range 31.2-40.0). Two of them died in the neonatal period and one received palliative care. In all of the latter cases anhydramnios developed throughout the pregnancy despite correct placement of the shunt. 7 pregnancies were terminated after detection of severe other defects and one fetus died unexpectedly 3 weeks after VAS. No survivor needed dialysis in the first year of life. The mean nadir creatinine in the first week was 0.65mg/dl (range 0.36-1.2), in the first month 0.38mg/dl (0.17-0.63) and in the first year 0.25mg/dl (range 0.16-0.36). All 3 females showed an adverse outcome.

Conclusion First trimester VAS can be offered for fetal megacystis. We were able to preserve renal function in all of the survivors. However, additional anomalies or multilevel obstructions are frequent and despite correct shunt placement may only be detected during the subsequent course of the pregnancy.

Publication History

Article published online:
29 August 2023