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Question 136
Delivery suite → Haemorrhage
Classification
Question
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An unsensitised RhD-negative woman at 34 weeks has a significant APH. A standard dose of anti-D immunoglobulin is given. Kleihauer testing subsequently demonstrates a fetomaternal haemorrhage exceeding that covered by the administered dose. What is the most appropriate next step?
Question Stem
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Options
A
No further treatment because anti-D has already been administered
B
Repeat anti-D only if another episode of vaginal bleeding occurs
C
Repeat the Kleihauer test after delivery and defer further treatment until then
D
Give additional anti-D according to the quantified fetomaternal haemorrhage
E
Replace anti-D with corticosteroids because the pregnancy is preterm
Explanation
APH is a potentially sensitising event in an unsensitised RhD-negative woman. Kleihauer testing is used to quantify fetomaternal haemorrhage so that the anti-D dose can be adjusted when the haemorrhage exceeds the amount covered by the standard dose. The test is therefore relevant to anti-D dosing, not to diagnosing placental abruption. Failure to provide sufficient anti-D after a large fetomaternal haemorrhage may leave fetal RhD-positive cells inadequately covered and increase the risk of maternal sensitisation.
Option Validity
A) The initial anti-D dose may be insufficient when the quantified fetomaternal haemorrhage exceeds the volume covered by that dose.
B) Additional anti-D may be required for the current sensitising event and should not depend on a further episode of bleeding.
C) Necessary additional anti-D prophylaxis should not routinely be deferred until after delivery.
E) Antenatal corticosteroids and anti-D immunoglobulin address entirely different clinical risks and are not interchangeable.
Further Reading
RCOG Green-top Guideline No. 63. Antepartum Haemorrhage. Royal College of Obstetricians and Gynaecologists; 2011.