Antenatal care: amniotic fluid disorders: practice question

A OBG question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

OBG · Antenatal care: amniotic fluid disorders

Sample item

A 32-year-old woman at 34 weeks has a uterus larger than dates, a tense abdomen and an amniotic fluid index of 30 cm. Ultrasound shows no stomach bubble in the fetus. Which fetal condition is most likely?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Oesophageal atresia

Polyhydramnios (AFI above 24 to 25 cm) results when the fetus cannot swallow amniotic fluid, as in oesophageal atresia (absent or small stomach bubble) and duodenal atresia (double bubble), or when there is excess production, as in maternal diabetes. Renal agenesis and obstructive uropathy cause oligohydramnios because urine contributes to the fluid.

Option by option

  • A. Renal agenesis

    Renal agenesis gives oligohydramnios with absent bladder, not polyhydramnios.

  • B. Oesophageal atresia (correct)

    Correct. A fetus that cannot swallow produces polyhydramnios and an absent stomach bubble.

  • C. Fetal growth restriction from placental insufficiency

    Placental insufficiency usually reduces liquor volume and gives oligohydramnios.

  • D. Posterior urethral valves

    Posterior urethral valves give a distended bladder and oligohydramnios.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More OBG questions

Questions about this OBG question

What is the answer to this OBG question?

The best answer is B, Oesophageal atresia. Polyhydramnios (AFI above 24 to 25 cm) results when the fetus cannot swallow amniotic fluid, as in oesophageal atresia (absent or small stomach bubble) and duodenal atresia (double bubble), or when there is excess production, as in maternal diabetes.

Why is "Renal agenesis" not the answer?

Renal agenesis gives oligohydramnios with absent bladder, not polyhydramnios.

Why is "Fetal growth restriction from placental insufficiency" not the answer?

Placental insufficiency usually reduces liquor volume and gives oligohydramnios.

Why is "Posterior urethral valves" not the answer?

Posterior urethral valves give a distended bladder and oligohydramnios.

What concept does this question test?

It tests Antenatal care: amniotic fluid disorders in OBG. Renal agenesis and obstructive uropathy cause oligohydramnios because urine contributes to the fluid.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Antenatal care: amniotic fluid disorders?

Learn management algorithms as steps: PPH, eclampsia, ectopic pregnancy. Then use the flashcards and the other OBG questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.