Which condition is typically associated with oligohydramnios and can lead to pulmonary hypoplasia due to lack of fetal urine production?

Which condition is typically associated with oligohydramnios and can lead to pulmonary hypoplasia due to lack of fetal urine production?

• A. Renal agenesis
• B. Gastroschisis
• C. Omphalocele
• D. Ureteropelvic junction obstruction

Answer: (A)

Fetal urine is the major contributor to amniotic fluid in the second and third trimesters, so when urine production falls to zero, amniotic fluid becomes severely low (oligohydramnios). With insufficient fluid, the fetus’s lungs don’t have the space and mechanical milieu needed to develop properly, leading to pulmonary hypoplasia. Renal agenesis—the absence of functional kidneys—produces no fetal urine, making this the typical scenario that links oligohydramnios to pulmonary hypoplasia. The other conditions involve abdominal wall defects or urinary tract obstructions, which do not inherently cause complete lack of urine production and thus are not the classic cause of this sequence.

Fetal urine is the major contributor to amniotic fluid in the second and third trimesters, so when urine production falls to zero, amniotic fluid becomes severely low (oligohydramnios). With insufficient fluid, the fetus’s lungs don’t have the space and mechanical milieu needed to develop properly, leading to pulmonary hypoplasia. Renal agenesis—the absence of functional kidneys—produces no fetal urine, making this the typical scenario that links oligohydramnios to pulmonary hypoplasia. The other conditions involve abdominal wall defects or urinary tract obstructions, which do not inherently cause complete lack of urine production and thus are not the classic cause of this sequence.