The pattern of massive obstetrical transfusion and the risk of severe maternal morbidity: A nationwide retrospective cohort study in China.

OBJECTIVE

To investigate the pattern of massive obstetrical transfusion in China and its effect on severe maternal morbidity (SMM).

METHODS

This nationwide retrospective cohort study enrolled all women with a pregnancy of more than 14 weeks duration who received at least 4 units of packed red blood cells (PRBCs) within 24 h after delivery in 64 tertiary hospitals in China from January 1, 2009, to June 30, 2019. Multivariate log-binomial regression models were used to estimate adjusted relative risks and 95% confidence intervals for the associations between the pattern of obstetrical transfusion and SMM.

RESULTS

A total of 8515 women were enrolled during the study period. The ratio of fresh frozen plasma (FFP) to PRBCs increased dramatically from less than 1:1 to 1:1 from 2009 to 2019, followed by a decrease of the incidence of SMM (from 31.3% in 2009 to 20.0% in 2019). After adjusting, the risks of SMM were generally higher in women with an FFP/PRBCs ratio of >1:2 to <1:1 and >1:1, but there was no significant difference in the risk of SMM in women with an FFP/PRBCs ratio of 1:1, when compared with women with an FFP/PRBCs ratio of ≤1:2. However, subgroup analysis showed that a 1:1 ratio of FFP/PRBCs resulted in the lowest risk of SMM in women with postpartum blood loss of 2500 mL or more, while a ≤1:2 ratio of FFP/PRBCs resulted in the lowest risk of SMM in women with postpartum blood loss of less than 2500 mL.

CONCLUSION

A 1:1 ratio of FFP/PRBCs resulted in best maternal outcomes in women with postpartum blood loss of 2500 mL or more.