Incidence and risk factors predicting blood transfusion in caesarean section.

Background: Routine preoperative evaluation for caesarean section (CS) has commonly included a blood type and screen evaluation due to risk of blood transfusion. However, there have been no objective local data to support such practices.

Aims: To evaluate the cost-effectiveness of blood type and screen testing for CS.

Methods: This retrospective study reviewed all singleton CS at a tertiary hospital using data from Blood Bank Registry and Obstetric Database, from 1 January 2004 to 31 December 2005. Clinical variables including demographic characteristics, estimated blood loss, indications for CS, preoperative haemoglobin and indications for transfusions were gathered. All patients who had blood transfusion recorded in Obstetric Database or in Blood Bank Registry had their medical records reviewed by two reviewers to confirm accuracy and identify risk factors for haemorrhage.

Results: Of 2212 patients with singleton pregnancy who underwent CS, 14 (0.63%) required a blood transfusion. The risk of blood transfusion for elective and emergency CS are 3.9 per 1000 and 9.8 per 1000, respectively. In the absence of risk factors identified in this study, no women (of a total of 1293 elective CS) required blood transfusion.

Conclusion: In the absence of significant risk factors for haemorrhage at CS in a tertiary setting, routine blood type and screen testing does not enhance patient care. In the rare event that a patient without previously identifiable risk factors requires an urgent blood transfusion, O negative blood could be given in the interim pending formal determination of type and cross-match.