Strength and limitations
The strength of this study is that it could be considered a regional cohort study. Given the established systems of centralisation in Satsuma Peninsula, most severe PPH cases, with rare exceptions, are transferred to either of the two hospitals included in this study.
This study has some limitations that must be acknowledged. First, this study included multiple facilities and the number of providers who attended the programme differed in each facility; thus, there may be some differences in the estimated blood loss and first aid for PPH at each facility. Obstetricians tended to underestimate the amount of blood loss.23 Thus, the recruitment of more patients and the study being conducted after all providers have completed the J-MELS programme are desirable. However, to overcome this problem, we used the SI in our analysis in addition to the amount of blood loss. The SI has been reported to be a useful predictor for early awareness of severe PPH.9,24-26 In this study, the median SI on arrival decreased from 0.85 in period 1 to 0.77 in period 2. This fact supports the lower blood loss at the referring hospitals in period 2 than in period 1. Hence, the amount of blood loss at the referring hospitals is considered to be reliable.
Second, this study may not have included mild cases in period 1; thus, the improvement observed could be explained by the increase of mild cases of PPH in period 2. Interpretation
In the J-MELS programme, an earlier transfer was the emphasised point, and over triage was tolerated. However, the fact that the cases of hysterectomy and IVR did not decrease indicated that the increase in mild cases was not the only reason for the improvement observed. This result indicates that the occurrence of severe PPH in this area may be increasing. There have been some reports of increases in severe cases of PPH.2-4,27-29 In the United States, the frequency of PPH with transfusion increased three-fold from 1999 to 2008.3 Advanced maternal age (≥35 years) is another risk factor for PPH. The mean maternal age increased from 31.1 years to 34.0 years between the two periods. These facts indicate that not only mild PPH transfers increased but the occurrence of PPH also increased. Therefore, the reduction in the massive transfusion rate may be the effect of the J-MELS programme. In Japan, the frequency of maternal deaths due to PPH decreased from 29% in 2010 to 7% in 2017.20 Because our study population was small, we could not confirm the reduction of maternal death, but there was a reduction in the massive transfusion rate among cases of inter-hospital transfer. The simulation-training programme changed providers’ behaviours and led to a decrease in the rate of massive transfusion. Although further study is needed, such training will have the potential to decrease maternal death in women with severe PPH instead of the recent trend of increasing maternal PPH.