Functional urinary tract obstruction developing in fetuses with isolated gastroschisis

To evaluate the frequency and natural history of urinary tract abnormalities developing in fetuses presenting with initially isolated gastroschisis.

Serial ultrasounds were performed prospectively on fetuses identified by our prenatal diagnosis program as having a gastroschisis. When abnormalities in the urinary tract were identified prenatally, newborns were evaluated by a pediatric urologist.

Over a 1-year period four out of 12 fetuses with gastroschisis developed deformations of the urinary tract. In three fetuses the bladder herniated through the abdominal wall defect. Two also had upper tract dilatation. A fourth fetus developed bilateral hydronephrosis with a normally situated bladder. Once the gastroschisis was repaired none of the newborns had evidence of structural obstruction of the urinary tract, however, hydronephrosis with or without reflux persisted for several months.

Deformations of the fetal urinary tract can develop secondary to gastroschisis. They do not appear to represent separate malformations and evaluation with fetal karyotyping may not be indicated. When hydronephrosis is present ongoing urologic evaluation of the neonate is indicated.