Aetiology and treatment of severe postpartum haemorrhage

Abstract

This thesis is comprised of three studies focusing on severe postpartum haemorrhage (PPH).
PPH is a major cause of maternal morbidity and mortality worldwide. Risk factors include
retained placenta, prolonged duration of the third stage of labour, previous caesarean section, and
operative vaginal delivery. Occurrence and development of PPH are, however, unpredictable and
can sometimes give rise to massive haemorrhage or even hysterectomy and maternal death.
Severe haemorrhage can lead to coagulopathy causing further haemorrhage and requiring
substitution with blood transfusions.
The aim of this thesis was to investigate causes of severe PPH and investigate methods of early
prevention.
The first study was a randomised controlled double-blinded trial investigating the effect of
treatment with pre-emptive fibrinogen on women with severe PPH. The primary outcome was
the need for red blood cell transfusion at 6 weeks postpartum. A total of 249 women were
randomised to either 2 grams of fibrinogen or placebo. The mean concentration of fibrinogen
increased significantly in the intervention group compared to the placebo group (0.40 g/L,
confidence interval: 0.15-0.65), but there was no difference in the need for postpartum blood
transfusions (relative risk 0.95, confidence interval: 0.15-1.54). No thromboembolic
complications were detected.
The second study was a population-based observational study including 245 women receiving
10 RBCs due to PPH. The cohort was identified by combing data from The Danish Transfusion
Database with The Danish Medical Birth Registry, with further data extraction and validation
through review of patient charts. The main causes of massive postpartum transfusion were atony
(38%) and abnormal invasive placenta (25%). Two of the women in the cohort died, an
additional six had a cardiac arrest, and a total of 128 women (52%) required a hysterectomy.
Hysterectomy was associated with increased blood loss, increased number of blood transfusions,
a higher fresh frozen plasma to red blood cell ratio (p=0.010), and an increased number of red
blood cells before first platelet transfusion (p=0.023). Hysterectomy led to haemostasis in only
70% of cases.
The third study was a register-based cohort study, including 43,357 vaginal deliveries from two
large Danish maternity units. Different cut-offs were used to define PPH. There was a difference
in distribution of causes depending on the cut-off used, with atony playing a decreasing role and
a retained placenta an increasing role the higher the cut-off used. In a multivariate linear
regression model retained placenta was identified as a strong predictor of quantity of blood loss.
The duration of the third stage of labour was a very weak predictor after adjusting for the
influence of a retained placenta.
In conclusion, an improved diagnosis of the causes of PPH especially retained placenta, together
with an early recognition and treatment of coagulopathy, seem to be important in reducing severe
PPH in an aim to minimize associated maternal morbidity.
OriginalsprogEngelsk
Antal sider102
StatusUdgivet - 2017

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