Which of the following is listed as a cause of oligohydramnios related to fetal underperfusion?

• A. Intrauterine growth restriction due to placental insufficiency
• B. Rupture of membranes
• C. Chorioamnionitis
• D. Placental abruption

Answer: (A)

Oligohydramnios that stems from fetal underperfusion happens when placental insufficiency reduces uteroplacental blood flow, leading to chronic fetal hypoxia. This drop in oxygen and nutrients decreases renal perfusion, so the fetus produces less urine—the main source of amniotic fluid after midgestation—which results in low amniotic fluid volume.

Intrauterine growth restriction due to placental insufficiency is a classic example of fetal underperfusion: the compromised placental blood flow causes slowed fetal growth and reduced urine output, directly producing oligohydramnios.

Rupture of membranes would cause fluid loss directly, not from reduced fetal urine production. Chorioamnionitis is an infection, not a perfusion-related cause of oligohydramnios. Placental abruption can cause distress but the specific link to oligohydramnios via underperfusion is best represented by IUGR from placental insufficiency.