Antenatal care: symmetric versus asymmetric fetal growth restriction: 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: symmetric versus asymmetric fetal growth restriction

Sample item

A fetus at 32 weeks shows head circumference, abdominal circumference and femur length all below the 3rd centile with normal liquor and umbilical Doppler. Which cause is most likely?

AMaternal diabetes with macrosomiaBConstitutionally large motherCPlacental insufficiency from late-onset pre-eclampsiaDAn early insult such as chromosomal abnormality or congenital infection

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

The answer and the reasoning

D. An early insult such as chromosomal abnormality or congenital infection

Symmetric restriction reflects reduced cell number from an insult in early pregnancy, such as aneuploidy, TORCH infection or teratogens. Asymmetric restriction arises later from placental insufficiency with head-sparing and abnormal Doppler. Further work-up includes karyotype and infection screen.

Option by option

A. Maternal diabetes with macrosomia
Diabetes usually causes large rather than small fetuses.
B. Constitutionally large mother
A large mother would not be expected to have a growth-restricted fetus.
C. Placental insufficiency from late-onset pre-eclampsia
Late placental insufficiency produces asymmetric growth with Doppler changes.
D. An early insult such as chromosomal abnormality or congenital infection (correct)
Correct. A global reduction in all parameters points to an early insult.

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.

Questions about this OBG question

What is the answer to this OBG question?

The best answer is D, An early insult such as chromosomal abnormality or congenital infection. Symmetric restriction reflects reduced cell number from an insult in early pregnancy, such as aneuploidy, TORCH infection or teratogens.

Why is "Maternal diabetes with macrosomia" not the answer?

Diabetes usually causes large rather than small fetuses.

Why is "Constitutionally large mother" not the answer?

A large mother would not be expected to have a growth-restricted fetus.

Why is "Placental insufficiency from late-onset pre-eclampsia" not the answer?

Late placental insufficiency produces asymmetric growth with Doppler changes.

What concept does this question test?

It tests Antenatal care: symmetric versus asymmetric fetal growth restriction in OBG. Asymmetric restriction arises later from placental insufficiency with head-sparing and abnormal Doppler. Further work-up includes karyotype and infection screen.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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: symmetric versus asymmetric fetal growth restriction?

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.