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Three Part Question

In [a pregnant patient who is rhesus negative with closed abdominal trauma] is [rhesus anti d prophylaxis effective] at [improving outcome for foetus]?

Clinical Scenario

A pregnant patient of 18 weeks gestation presents to the emergency department having fallen down some stairs. The patient’s blood group is Rhesus negative and you are not sure of the blood group of the foetus. You wonder if it would be wise to administer prophylactic Rh-anti D to protect the foetus from potential problems.

Search Strategy

Medline 1950 to 11/2007 using Ovid Interface
EMBASE 1980-2008 Week 1
The Cochrane Library

[{exp pregnancy/ OR pregnancy.mp OR exp pregnancy complications/ OR pregnancy complications.mp.} AND {exp “wounds and injuries”/ OR trauma.mp. OR exp wounds, nonpenetrating/ OR exp abdominal injuries/ OR abdominal trauma.mp. OR blunt abdominal trauma.mp.} AND {exp emergency treatment/ OR emergency treatment.mp. OR emergenc$.mp.} AND {rhesus d.mp. OR exp “Rho(D) immune globulin”/ OR anti d immunoglobulin.mp.}] LIMIT to human and English language

Search Outcome

8 papers were found of which 5 were found to be relevant.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Fisher M 1989 Israel	Gravide 3 para 2 28yrs old healthy with A-negative blood type and anti-D titre of 1 : 64 admitted to the ED following an MVA with blunt trauma to the abdomen and left arm	Case report	No KBT was done following the accident. 7 days following the accident an emergency caesarean was performed due to placental abruption. An hydropic male infant was delivered. A KBT test performed prior to the CS showed 4% foetal cells (apx 160ml of foetal blood).	The haemolytic process can be very rapid and despite previous immunization in her first pregnancy of 300 µg of Rhesus anti-D obviously it was not enough to compensate.	Small case study. No comment on amount of anti-D that may have alterned the chain of events.
Weinberg L et al 2005 Australia	Pregnant trauma patients	Sensitization can occur in all rhesus negative women ecposed to as little as 0.1ml and all unsensitized Rh-negative women who suffer trauma should be offered Rh D immunoglobulin.	Sensitization can occur in all rhesus negative women ecposed to as little as 0.1ml and all unsensitized Rh-negative women who suffer trauma should be offered Rh D immunoglobulin.	In Australia the recommended dose is 125 µg which is sufficient to prevent immunization by a foetomaternal haemorrhage of 2.5ml of foetal red cells which is 5ml of whole blood. It should be administered by deep IM injection as soon as possible for maximum protection.	No patient studies. No Search strategy
Muench MV, Canterino JC, 2007 USA	Pregnant patients who have undergone trauma.	Review of literature concerning trauma in pregnancy	A Kleihauer-Betke test (KBT) should be considered in all trauma patients.	Any Rhesus negative patient with a positive KB test should be treated with Rh-immune globulin 300µg initially and an additional 300µg for each 30ml of estimate whole foetal blood.	No study group. No search strategy

Comment(s)

A rhesus D positive baby in a rhesus D negative mother can cause her circulation to produce anti-D IgG antibodies (isoimmunisation) if foetal cells leak into the maternal circulation which may happen at delivery and in trauma even mild in severity. Tests for D antibodies are done in all Rh-ve mothers at booking, 28 and 34 weeks gestation. Anti-D immunoglobulin is routinely given antenatally at 28 weeks and 34 weeks. Rhesus haemolytic disease is a disease that can vary in severity from mild anaemia to hydrops fetalis or still birth. The Rhesus D antigen has been found to be well established in a 6week old foetus [Murphy] and although the foetus at that age is protected to a large extent by the pelvis the chance of foetal blood leaking into the maternal circulation in the event of an abdominal trauma is highly likely and may infact occur before the standard administration at 28 weeks. Once antibody formation has occurred the administration of anti-D is ineffective so any delay in administering it could result in devastating consequences. Tests to detect the presence of foetal cells in the maternal circulation may be inaccurate if only a few cells are present but that does not mean that the risk of alloimmunization does not exist. Using guidelines in the BNF for Anti-D Rho Immunoglobulin a dose of 250IU under 20 weeks gestation and over 20 weeks a dos of 500IU should be given immediately. This dose is considered enough to cover a standard 4ml bleed, a KBT must be sent off immediately to ascertain the size of any potential FMH in order that a further dose of anti-D can be given if necessary.

Clinical Bottom Line

Prophylactic anti-D should be given in all cases of abdominal trauma where a mother is known to be rhesus negative and the father’s blood group is not certain.

References

1. Fisher M. Acute Rh isoimmunization following abdominal trauma associated with late abruption placenta Acta Obstetricia et Gynecologica Scandinavica. 68(7) 1989;657-659
2. Weinberg L et al. The pregnant trauma patient. Anaesthesia and Intensive Care. 33(2) 2005;167-180
3. Muench MV, Canterino JC Trauma in Pregnancy. Obstetrics and Gynecology Clinics of North America. 34(3) 2007;555-583