Incidence, trends and risk factors for obstetric massive blood transfusion in China from 2012 to 2019: an observational study

Objectives This study aims to use the high-quality national monitoring data from the China's National Maternal Near Miss Surveillance System (NMNMSS) to ascertain the incidence, trends and risk factors of obstetric massive blood transfusion (MBT) from 2012 to 2019 in China and determine its clinical outcomes. Settings Observational study of hospitalised pregnancies who had given birth or ended their pregnancy among member hospitals of NMNMSS. Participants 11 667 406 women were included in this study. Primary and secondary outcome measures We screened for the incidence, trends, risk factors and main reasons for obstetric MBT, and the outcomes after obstetric MBT. MBT was defined as the transfusion of >= 5 units of red blood cells or >= 1000 mL of whole blood. The incidence of MBT was defined as the MBT cases per 10 000 pregnancies. Results Obstetric MBT occurred in 27 626 cases, corresponding to an incidence of 23.68 per 10 000 maternities, which exhibited an increasing trend in China during 2012-2019 (14.03-29.59 per 10 000 maternities, p for trend <0.001). Obstetric MBT was mainly associated with amniotic fluid embolism, uterine atony, abnormal placenta, severe anaemia, ectopic pregnancy, abortion, caesarean section, advanced maternal age and multiparous from biological effect. While from sociological effects, uterine atony, severe anaemia and placenta previa are the top three complications which more likely to undergo obstetric MBT in the Chinese population. Overall, the secular trends of hysterectomy incidence (25.07%-9.92%) and MMR during hospitalisation (21.41 parts per thousand-7.48 parts per thousand) among women who underwent MBT showed decreasing trends (p for trend <0.001). Conclusion To minimise the incidence of obstetric MBT, more attention should be paid to education on the importance of the antenatal visit, evidence-based transfusion practice and females who are multiparous and have an advanced age, amniotic fluid embolism, uterine atony, severe anaemia and placenta previa.