Our study bears three important implications. First, in patients with PA-IUFD, the transfusion group bore lower fibrinogen levels and platelet counts; higher FDP, D-dimer, and PT, a tendency for tachycardia on admission, and a higher total blood loss compared to the non-transfusion group. Second, even when fibrinogen levels were normal on admission, these levels markedly declined in many patients in the transfusion group later. Third, we concluded that the JSOG DIC score may be used in patients with PA-IUFD.
On admission findings and blood loss
The transfusion group exhibited significantly lower fibrinogen and platelet counts, higher FDP, D-dimer, and PT on admission, and more blood loss compared to the non-transfusion group. It is not surprising that the transfusion group displayed more blood loss, but this was not associated with the mode or duration of delivery. Fibrinogen levels have been reported to be useful indicators of PPH severity and blood transfusion13, 14. In the present study, the ORs for blood transfusion were 5.4 and 4.7 for fibrinogen levels < 150 mg/dL and 200 mg/dL, respectively, suggesting that, in the cases with PA-IUFD, a fibrinogen level < 200 mg/dL can indicate a need for blood transfusion. In addition, a negative correlation was observed between fibrinogen levels and the total FFP transfusion volume, as reported by Matsunaga et al. for placental abruption cases16. Our data strongly support the importance of fibrinogen levels for transfusion in PA-IUFD. Interestingly, not only was the platelet count lower in the transfusion group, but also a count of 2×105/µL or less had high ORs for transfusion, indicating that transfusion is more likely to be required in PA-IUFD, even for normal to mildly low platelet counts. The FDP and D-dimer levels were significantly higher in the transfusion than the non-transfusion group and correlated strongly with FFP transfusion. Although a correlation between the severity of placental abruption and pre-delivery FDP and D-dimer values has been reported17, the correlation between blood transfusion and PA-IUFD cases has not been described yet. In placental abruption, especially in severe cases associated with IUFD7, the fibrinolytic system is activated due to consumptive coagulopathy, resulting in FDP and D-dimer release. Therefore, FDP and D-dimer levels may be useful indicators of transfusion in PA-IUFD. In addition, the heart rate was positively correlated with FFP transfusion. The heart rate can be evaluated easily and quickly and, as tachycardia is associated with a decrease in the circulating blood volume, it may be a useful indicator for blood transfusion.
To the best of our knowledge, this is the first study to suggest a relationship between blood transfusion and heart rate for PPH, but our sample size was small; therefore, further studies are required. Intriguingly, the SI was not significantly different in this study. This may be because placental abruption is frequently complicated with HDP. The incidence of chronic hypertension (CH) and gestational hypertension in normal pregnancies in Japan have been reported to be 0.6–1.5% and 6–25%, respectively18–21, but 1/4 of placental abruption is complicated by CH22. In the present study, HDP was observed in approximately 30% of the patients. This suggests that changes in heart rate may be more important than SI in PA-IUFD because a decrease in blood pressure among hypertensive women does not initially increase SI. PT was significantly prolonged in the transfusion group, but the difference was small and in line with the study of Collins et al23, possibly due to fibrinogen depletion. However, this small difference is expected to be insufficient for it to be used as an indicator.
Changes in fibrinogen levels
Fibrinogen levels were markedly decreased after admission in the transfusion group. Although there were eight patients in the transfusion group with fibrinogen levels of > 200 mg/dL on admission, fibrinogen levels subsequently decreased in all patients. Furthermore, seven of the eight patients had decreased fibrinogen levels at the time of admission despite receiving FFP transfusion, suggesting that their coagulopathy was progressive and severe. A low platelet count suggests a progressive decline in fibrinogen levels. In a comparison of patients with fibrinogen levels of > 200 mg/dL on admission between the transfusion and non-transfusion groups, the platelet count on admission was 14.5×104/µL (7.1–23.8×104/µL) in the transfusion group and 21.0×104/µL (13.5–30.6×104/µL) in the non-transfusion group, with a tendency to be lower, albeit not significantly, in the transfusion group (p = 0.06). We conclude that, even when the fibrinogen level is normal on admission, if the platelet count is low, there is a possibility of progressive and severe coagulopathy; therefore, serial monitoring of fibrinogen is essential in patients with PA-IUFD.
JSOG DIC score
In Japan, the JSOG DIC score is used for the early diagnosis and treatment of PPH. It reflects clinical findings, vital signs, and laboratory data, and when it is ≥ 8 points, the patient is likely to progress to DIC.12
We propose blood loss, heart rate, fibrinogen level, platelet count, D-dimer, and FDP as deciding factors for initiating transfusion in patients with PA-IUFD, all of which are included in the JSOG DIC score. The JSOG DIC score was significantly higher in the transfusion than the non-transfusion group, highlighting the usefulness of the JSOG DIC score in PA-IUFD.