A Rare Case of A2+ve Blood Group in an Obstetric Emergency

Abstract

We present a rare case of A2+ve blood group with Placenta praevia with Obstetric Haemorrhage in mild hypovolemic shock. An emergency request for blood transfusion confounded the blood bank officer as the patient's blood was seemingly incompatible with all ABO blood groups. Further investigation revealed the patient's blood group to be a rare subtype of the A group known as A2+ve. This article highlights the need to be aware of such rare subgroups, especially in tertiary referral centres like ours, where unbooked Obstetric emergencies are encountered on a regular basis, so life-saving measures can be appropriately taken. CASe RepoRTA 31-year-old unbooked lady presented to the Obstetric emergency ward and a diagnosis of gravida 2, para 1, living 0 with 27 weeks of gestation with central placenta praevia with ante partum haemorrhage was made. She had undergone a previous caesarean section at term for a transverse lie and the baby was still-born. Patient had been treated for secondary infertility and conceived spontaneously ten years later with the present pregnancy. General examination revealed the patient to be in mild hypovolemic shock with a tachycardia of >130 beats/minute. Her blood pressure was 94/60 mmHg. Haemoglobin was 8.4 gm/dL. Blood group was A+ve but when sent for cross matching was found to be incompatible with all ABO groups. Senior blood bank officers were called in and further tests done indicated a rare subgroup of A2+ve. No blood in our bank and two other major blood banks was found compatible. Ultimately, four pints of compatible A2+ve blood was found after screening nearly 600 pints of A+ve blood at the Karnataka Red Cross Blood Bank. At present patient has received 3 pints of blood and antenatal steroids. Since she has no further bleeding we plan to monitor her as an inpatient till she crosses her period of viability or the fetus can sustain in an extra uterine environment, provided she has no further life threatening haemorrhage which would compromise either her or the baby. DiSCuSSionMassive obstetric haemorrhage is a major contributor towards maternal morbidity and mortality. The main causes are abruptio placentae, placenta praevia and postpartum haemorrhage [1]. Clinicians managing pregnant women should be equipped with the knowledge of blood and blood products and skills for managing massive obstetric haemorrhage. We are all familiar with the blood groups O, A, B discovered by K Landsteiner in 1900, by performing a series of mixing experiments with the blood of 22 colleagues in which red cells from each individual was mixed with the serum of each of the others. On the basis of the agglutination pattern that he observed, Landsteiner could establish three groups of individuals (A, B and O). Two years later, Landsteiner recognised a fourth (AB) group when the experiment was repeated on a larger group of subjects. Most clinicians are, however, unfamiliar with the fact that in 1911, Landsteiner detected the presence of subgroups of A, one of which was exhibiting weaker expression of th...

Amelioration in cross-matching policy with subtypes of A for priority-based demand

“…During an obstetric emergency, a patient with a blood type 𝐴 2 was identified (Padmasri et al, 2014).…”