Absence of one or both kidneys with pulmonary hypoplasia due to oligohydramnios is known as which condition?

• A. Renal agenesis
• B. Wilms tumor
• C. Posterior urethral valve obstruction
• D. Gastroschisis

Answer: (A)

The key idea is that fetal urine is a major contributor to amniotic fluid. When the kidneys are absent, the fetus produces little to no urine, leading to severe oligohydramnios. This lack of amniotic fluid restricts lung development, causing pulmonary hypoplasia, a hallmark seen with renal agenesis. So the condition described—absence of one or both kidneys with resulting oligohydramnios and pulmonary hypoplasia—is renal agenesis. The other options describe different renal or abdominal issues (a kidney tumor, urinary tract obstruction, or an abdominal wall defect) that do not involve the newborn lacking kidneys and do not specifically explain the oligohydramnios-pulmonary hypoplasia sequence.