A primigravida with O negative blood group delivered a baby with O positive blood group. While DCT was negative. What should be done next?

1. A

   Repeat DCT

2. B

   Give 300 mg of Anti-D to mother

3. C

   Give 150 mg of Anti-D to mother

4. D

   No need to give Anti-D to mother

Appeared in: AIIMS Delhi NO- 2019

Explanation

• The clinical situation presents a classic case for Rh prophylaxis: an Rh-negative mother has delivered an Rh-positive baby.
• The goal is to prevent the mother from developing her own anti-D antibodies, which could cause Hemolytic Disease of the Fetus and Newborn (HDFN) in future pregnancies.
• Administering Anti-D immune globulin neutralizes any fetal Rh-positive red blood cells that may have entered the maternal circulation during delivery.
• The standard postpartum dose is 300 µg, which should be administered within 72 hours of birth.
• The negative Direct Coombs' Test (DCT) confirms the baby is not currently affected by maternal antibodies, making this prophylactic measure appropriate and necessary.

Why Other Options Were Wrong

• Option A: Repeating the Direct Coombs' Test (DCT) is unnecessary. The initial negative result has already provided the needed information—that the baby's red cells are not coated with maternal antibodies. The priority is to administer the prophylactic Anti-D, not to repeat tests.
• Option C: A dose of 150 µg is insufficient for postpartum prophylaxis after a full-term delivery. Smaller doses (typically 50 µg) are reserved for events in the first trimester, such as a miscarriage or termination, where the volume of potential feto-maternal hemorrhage is much smaller.
• Option D: Withholding Anti-D is incorrect and poses a significant risk for future pregnancies. Without prophylaxis, the mother has a high chance of becoming sensitized, which can lead to severe anemia, hydrops fetalis, and even death for a future Rh-positive fetus.

Related Visual

Clinical Relevance

• Nursing practice connection: Knowing Rh isoimmunization prophylaxis helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
• Nurses play a critical role in preventing Rh isoimmunization by verifying maternal and infant blood types, checking Coombs' test results, and ensuring the timely administration of the correct dose of Anti-D immune globulin.
• Patient education is key. The nurse must explain to the mother why the injection is necessary for the health of her future children.
• It is a major patient safety issue. Failure to administer Anti-D when indicated is a preventable error with severe consequences for subsequent pregnancies.

How to Approach the Question

• First, identify the blood types and Rh factors of both the mother and the baby. Mother is O negative (Rh-negative), and the baby is O positive (Rh-positive).
• Recognize the clinical problem: There is a mismatch in Rh factor, creating a risk for maternal sensitization.
• Analyze the additional data provided: The mother is a primigravida (first pregnancy), and the baby's Direct Coombs' Test (DCT) is negative. This strongly suggests the mother is not yet sensitized.
• Recall the standard medical intervention for this specific scenario: Prophylactic administration of Anti-D immune globulin to the mother after delivery.
• Determine the correct dosage and timing for postpartum prophylaxis, which is 300 µg within 72 hours.
• Compare this standard of care with the given options to select the correct answer.

Concept Tested & Keywords

• Concept Tested: Rh isoimmunization prophylaxis
• Stem keywords: primigravida, O negative blood group, O positive blood group, DCT negative, postpartum
• Lead-in keywords: What should be done next?
• Clinical cues: The mismatch in Rh factor between mother (negative) and baby (positive) is the primary clinical cue indicating a risk of isoimmunization.

Question ID

QYMxl-so7exnkKyNwMlz42

Copy ID

Reference Book

E6 Obstetrics Williams p. 48-68