Anaemia a major indication for obstetric red cell transfusion in multiethnic population

Red cell transfusion at a high-volume tertiary hospital in Singapore has an incidence of 3.2 percent in a multiethnic obstetric population, according to a study. Anaemia during pregnancy is the most common reason for transfusion administration.

“Patient blood management strategies should focus on optimizing antenatal anaemia, reducing blood loss during delivery, and eliminating inappropriate transfusion,” said the researchers, led by Dr Eileen Lew, senior consultant for the Department of Women’s Anaesthesia at KK Women’s and Children’s Hospital, Singapore.

This retrospective cohort study identified all parturients who delivered a live infant or stillbirth from 2014 to 2015 and who received allogeneic blood transfusion during pregnancy and up to 6 weeks postnatally. The researchers reviewed medical records to obtain relevant demographic, obstetric, and transfusion data. They also performed a descriptive analysis of data using IBM SPSS Statistics software.

A total of 23,456 parturients were identified, of which 760 received red cell transfusion, resulting in a transfusion rate of 3.2 percent of 32 in 1,000 maternities. Overall, 1,675 red cell units were used in 863 transfusion episodes. [Singapore Med J 2022;doi:10.11622/smedj.2022082]

Anaemia in pregnancy (49.2 percent) and postpartum haemorrhage secondary to an atonic uterus were the most common indications for transfusion. Of note, transfusion was more frequently administered with caesarean than vaginal births (4.9 percent vs 2.4 percent).

Nearly 14 percent of transfusions were initiated with pretransfusion haemoglobin (Hb) ≥8.0 g/dL, while 37 percent of transfusions led to post-transfusion Hb >9.0 g/dL.

“Compared with rates of 0.1‒3.2 percent reported in the literature, the rate of obstetric red cell transfusion at our institution is considered high,” the researchers said. [Vox Sang 2015;108:37-45; Transfusion 2017;57:811-815; J Perinat Med 2019;47:195-199; Obstet Gynecol 2006;108:891-897]

Transfusion rates were influenced by maternal case-mix, hospital factors, and obstetric interventions, which accounted for 26 percent, 39 percent, and 8 percent of interhospital variations, respectively. [Vox Sang 2015;108:37-45]

While anaemia in pregnancy was the primary indication for transfusion in nearly half of the patients, this was not so in other studies that found maternal haemorrhage as the most common indication. [Obstet Gynecol 2014;123:126-33]

“Our finding is not surprising because the prevalence of anaemia in pregnancy is reportedly higher in Southeast Asia (44–53 percent) than in Europe (19–32 percent) and North America (17–31 percent), with iron and folate deficiencies as the most common aetiologies,” the researchers said. [https://apps.who.int/iris/bitstream/handle/10665/43894/9789241596657_eng.pdf?ua=1; Hematol Oncol Clin North Am 2011;25:241-259]

Anaemia in pregnancy remains a public health concern in developing countries, according to the researchers. If left untreated, it can result in adverse maternal and neonatal outcomes. [BMJ 2013;346:f3443; BMC Pregnancy Childbirth 2018;18:111; Br J Haematol 2017;177:884-895]

“Although many international and local guidelines have been developed for the screening and treatment of iron-deficiency anaemia in pregnancy, there is poor compliance related to individual knowledge gaps or variations in practice among physicians,” the researchers noted. [Obstet Gynecol 2008;112:201-207; Matern Child Health J 2017;21:1627-1633]

“A clinician’s knowledge, attitudes and experience are known to influence clinical practice,” they added.