Antenatal care: fetal and neonatal alloimmune thrombocytopenia: 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.

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OBG · Antenatal care: fetal and neonatal alloimmune thrombocytopenia

Sample item

A healthy primigravida has normal platelet counts, but her newborn has a platelet count of 12,000 per microlitre with intracranial haemorrhage. Maternal antibodies against the paternal platelet antigen HPA-1a are found. What is the diagnosis?

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

The answer and the reasoning

C. Neonatal alloimmune thrombocytopenia

In alloimmune thrombocytopenia the mother, who lacks HPA-1a, makes IgG antibodies against fetal platelets that cross the placenta. Unlike Rh disease, the first pregnancy can be affected, and the mother has a normal platelet count. Intracranial haemorrhage is the main danger, and treatment in later pregnancies uses maternal IVIG.

Option by option

  • A. HELLP syndrome

    HELLP is a maternal hypertensive condition and is not defined by antibodies to platelet antigens.

  • B. Gestational thrombocytopenia

    Gestational thrombocytopenia is benign and does not affect the fetus.

  • C. Neonatal alloimmune thrombocytopenia (correct)

    Correct. A normal maternal count with antibodies to a paternal platelet antigen fits.

  • D. Maternal immune thrombocytopenic purpura

    In maternal ITP the mother herself is thrombocytopenic.

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 C, Neonatal alloimmune thrombocytopenia. In alloimmune thrombocytopenia the mother, who lacks HPA-1a, makes IgG antibodies against fetal platelets that cross the placenta.

Why is "HELLP syndrome" not the answer?

HELLP is a maternal hypertensive condition and is not defined by antibodies to platelet antigens.

Why is "Gestational thrombocytopenia" not the answer?

Gestational thrombocytopenia is benign and does not affect the fetus.

Why is "Maternal immune thrombocytopenic purpura" not the answer?

In maternal ITP the mother herself is thrombocytopenic.

What concept does this question test?

It tests Antenatal care: fetal and neonatal alloimmune thrombocytopenia in OBG. Unlike Rh disease, the first pregnancy can be affected, and the mother has a normal platelet count. Intracranial haemorrhage is the main danger, and treatment in later pregnancies uses maternal IVIG.

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: fetal and neonatal alloimmune thrombocytopenia?

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.