Snap Shot A transabdominal ultrasound was performed at 20 weeks¹ gestation. The fetus is in breech presentation. There is an absence of amniotic fluid. (Oligohydramnios due to bilateral renal agenesis) Polyhydramnios Definition >1.5-2 L of amniotic fluid Causes associated with conditions of decreased fetal resorption of amniotic fluid as a result of impaired swallowing or a blocked GI tract esophageal / duodenal atresias anacephaly Oligohydramnios Definition < 0.5 L Causes associated with conditions of decreased fetal production of amniotic fluid as a result impaired fetal urine output bilateral renal agenesis posterior urethral valves (in males) newborns may have midline mass Complications decreased fetal lung maturity / hypoplasia