Anti-D immunoglobulin is given when the mother is Rh-negative and the baby is Rh-positive. When should immuno… - AIIMS M.Sc. Nsg Entrance exam-2026

AIIMS M.Sc. Nsg Entrance exam-2026

Obstetrics & Gynaecology

Easy

Appeared in: AIIMS M.Sc. Nsg Entrance exam-2026

Explanation

To prevent Rh sensitization, Anti-D immunoglobulin must be given to an Rh-negative mother after the birth of an Rh-positive baby.
The standard and critical window for this postpartum administration is within 72 hours of delivery.
This timeframe is crucial because it allows the administered antibodies to find and destroy any fetal Rh-positive red blood cells in the mother's circulation before her own immune system can produce permanent antibodies.
Administering the immunoglobulin within this 72-hour window reduces the rate of alloimmunization by 90 percent.

Option A: Waiting 7 days is too long. By this time, the mother's immune system may have already recognized the fetal Rh-positive cells and started producing its own antibodies, making the Anti-D immunoglobulin ineffective.
Option C: While administering within 2 hours is not harmful, it is unnecessarily restrictive. The established window of effectiveness extends up to 72 hours, providing a more practical timeframe for blood typing and administration.
Option D: Waiting 10 days is far too late. The risk of maternal sensitization is very high by this point, and the protective effect of the immunoglobulin would be lost. Some protection may be offered up to 28 days, but this is not the standard of care and is only done if the initial dose was missed.

Visual 1: Diagram: Pathophysiology of Rh Isoimmunization - A visual showing an Rh-negative mother and an Rh-positive fetus. Illustrate how fetal RBCs cross the placenta during the first delivery, causing the mother to produce anti-D antibodies. Then, show how these antibodies cross the placenta in a subsequent pregnancy to attack the new fetus's RBCs.
Visual 2: Infographic: Anti-D Immunoglobulin Administration Timeline - A clear timeline showing the key points for administration: at 28 weeks gestation, within 72 hours postpartum, and after any potential sensitizing event (e.g., amniocentesis, miscarriage).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Administration timing of Anti-D immunoglobulin for Rh incompatibility as background academic context rather than a clinical decision trigger.
The primary clinical goal of administering Anti-D immunoglobulin is to prevent Hemolytic Disease of the Fetus and Newborn (HDFN) in subsequent pregnancies, a condition that can lead to severe fetal anemia, heart failure, and death.
Nurses play a critical role in ensuring timely administration by verifying maternal and infant blood types, obtaining consent, and educating the patient on the importance of this preventive measure for future family planning.
What if the mother refuses the injection? The nurse must document the refusal after thoroughly explaining the risks to future pregnancies. The mother's autonomy must be respected, but the education and documentation are crucial for legal and ethical reasons.

How to Approach the Question

First, identify the core concept of the question: it's about Rh incompatibility between an Rh-negative mother and an Rh-positive baby.
Recall the purpose of Anti-D immunoglobulin (RhoGAM): to prevent the mother from developing antibodies against the baby's Rh-positive blood.
Focus on the specific question asked: the timing of administration after delivery.
Access your knowledge about the critical window for postpartum prophylaxis. Remember that the goal is to neutralize fetal cells before the mother's immune system mounts a full response.
Evaluate the options based on this critical window. The standard, evidence-based timeframe is 'within 72 hours'.
Eliminate other options: 2 hours is too narrow, while 7 and 10 days are too late and risk treatment failure.

Concept Tested & Keywords

Concept Tested: Administration timing of Anti-D immunoglobulin for Rh incompatibility.
Stem keywords: Anti-D immunoglobulin, Rh-negative mother, Rh-positive baby
Lead-in keywords: When should be administered

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