Question

The following are causes of oligohydramnios EXCEPT?

• A. IUGR
• B. Postmaturity
• C. Maternal dehydration
• D. Labetolol

Hint:

Think which antihypertensive is safe in pregnancy versus ACE inhibitors and NSAIDs that drop fetal urine.

Answer 1

The Correct Option is D

Step 1: Frame the question around fetal kidneys. After the first half of pregnancy, the volume of liquor depends mainly on how much urine the fetus makes. Low liquor (oligohydramnios) therefore points to reduced fetal urine, impaired placental flow, or maternal fluid loss.

Step 2: Check each listed option. IUGR has placental insufficiency, which diverts blood from the fetal kidneys and drops urine output. Postmaturity carries a failing placenta, so fluid declines as the pregnancy passes term. Maternal dehydration lowers the mother's circulating volume and is a quick, correctable trigger of low liquor.

Step 3: Now test Labetalol. It is an alpha plus beta adrenergic blocker chosen for pregnancy hypertension. It does not impair fetal renal perfusion the way ACE inhibitors, ARBs or NSAIDs do, so it does not lower amniotic fluid.

Step 4: The drug that is NOT linked with oligohydramnios is therefore Labetalol, which is the requested exception.

\[\boxed{\text{Labetalol}}\]