Which of the following is the cause of asymmetric IUGR?

UPUMS Nsg officer-2023

Obstetrics & Gynaecology

Easy

Appeared in: UPUMS Nsg officer-2023

Explanation

Asymmetric IUGR results from an insult that occurs late in pregnancy, typically in the second half or third trimester.
The underlying cause is most often uteroplacental insufficiency, where the placenta cannot provide adequate oxygen and nutrients to the fetus.
Pregnancy-induced hypertension (PIH) is a classic maternal vascular disease that impairs placental blood flow, leading to placental insufficiency.
This insufficiency triggers a 'brain-sparing' effect, where blood is shunted to the fetal brain, causing the head to grow normally while the abdomen and overall weight lag, resulting in an asymmetric growth pattern.

Option B: Gestational diabetes is most commonly associated with fetal macrosomia (large for gestational age) due to high maternal glucose levels acting as a growth stimulant.
Option C: Structural defects are intrinsic fetal problems that occur early in gestation. The insult affects all cells from an early stage, leading to a proportional, or symmetric, growth restriction.
Option D: Intrauterine infections (e.g., TORCH) are also an early-onset insult to the fetus. They disrupt cell division and development globally, resulting in symmetric IUGR.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Asymmetric Intrauterine Growth Restriction (IUGR) as background academic context rather than a clinical decision trigger.
Nurses play a vital role in monitoring blood pressure and screening for proteinuria in all pregnant women to detect PIH and preeclampsia early.
For mothers diagnosed with PIH, nurses assist in managing antenatal surveillance, which includes serial ultrasounds and Doppler flow studies to monitor fetal growth and placental function.
Early identification of IUGR allows for timely interventions, such as increased fetal monitoring, administration of corticosteroids for fetal lung maturity, and planning for delivery to prevent adverse outcomes like stillbirth.

How to Approach the Question

First, identify the key clinical term in the question: 'asymmetric IUGR'.
Recall the fundamental pathophysiology: asymmetric IUGR is a 'late' pregnancy problem caused by placental failure, whereas symmetric IUGR is an 'early' pregnancy problem caused by an intrinsic fetal issue.
Evaluate each option based on this 'early vs. late' framework.
Pregnancy-induced hypertension is a maternal vascular disease that affects placental function, typically in the latter half of pregnancy. This matches the profile for asymmetric IUGR.
Structural defects and intrauterine infections are events that occur early in fetal development, which would cause symmetric IUGR. Therefore, eliminate these options.
Gestational diabetes is primarily known to cause fetal overgrowth (macrosomia), not restriction. Eliminate this option.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1056-1058