Embryology: placenta accreta: practice question

A Anatomy 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.

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Anatomy · Embryology: placenta accreta

Sample item

A multiparous woman with previous caesarean sections has a placenta that does not separate after delivery and requires hysterectomy. Histology shows chorionic villi attached directly to myometrium. What developmental deficiency permits this?

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

The answer and the reasoning

B. Deficient decidua basalis

The decidua basalis normally forms the plane of cleavage at separation of the placenta. When it is deficient, as over a uterine scar, villi anchor to myometrium (accreta), into it (increta) or through it (percreta), causing catastrophic haemorrhage after delivery.

Option by option

  • A. Failure of the amnion to fuse with the chorion

    The amnion and chorion fuse normally and this does not influence placental separation.

  • B. Deficient decidua basalis (correct)

    Correct. A deficient decidua basalis lets villi invade the myometrium.

  • C. Excess cytotrophoblast layer

    Excess cytotrophoblast is not the cause; the problem is the lack of the decidual plane.

  • D. Absent syncytiotrophoblast

    The syncytiotrophoblast invades normally and is present in accreta.

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 Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is B, Deficient decidua basalis. The decidua basalis normally forms the plane of cleavage at separation of the placenta.

Why is "Failure of the amnion to fuse with the chorion" not the answer?

The amnion and chorion fuse normally and this does not influence placental separation.

Why is "Excess cytotrophoblast layer" not the answer?

Excess cytotrophoblast is not the cause; the problem is the lack of the decidual plane.

Why is "Absent syncytiotrophoblast" not the answer?

The syncytiotrophoblast invades normally and is present in accreta.

What concept does this question test?

It tests Embryology: placenta accreta in Anatomy. When it is deficient, as over a uterine scar, villi anchor to myometrium (accreta), into it (increta) or through it (percreta), causing catastrophic haemorrhage after delivery.

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 Embryology: placenta accreta?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy 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.