Fibrinogen plasma concentration before delivery is not associated with postpartum haemorrhage: a prospective observational study.

Background: Low plasma fibrinogen concentration has been linked to postpartum haemorrhage. The primary aim of this study was to assess whether fibrinogen concentration at admission before labour is associated with severe postpartum haemorrhage. Secondary aims were to describe fibrinogen concentration before and after labour and to identify predictors for severe postpartum haemorrhage.

Methods: 1951 healthy women were included in a prospective observational study. Fibrinogen concentration was determined at admission to the labour ward and in a subgroup of women (n=80) also after the placenta was delivered. Bleeding volume postpartum was estimated by weighing surgical sponges and pads and by measuring collected blood. Predictors for severe postpartum haemorrhage (>1000 ml) were identified with bivariate and multivariate regression analyses.

Results: Mean fibrinogen concentration was 5.3 (SD 0.8) g litre(-) (1). Median estimated blood loss was 450 (range 70-4400) ml and 250 (12.8%) women bled >1000 ml. Fibrinogen concentration was not correlated with postpartum haemorrhage in the entire cohort (r(s)=0.003, P=0.90) or in any subgroup. Fibrinogen concentration was not associated with bleeding >1000 ml (odds ratio 1.01 (CI 95% 0.85-1.19), P=0.93) and did not differ significantly before and after delivery. Oxytocin stimulation, instrumental delivery, Caesarean section and exploration of uterus were identified as independent predictors of haemorrhage >1000 ml.

Conclusions: Fibrinogen plasma concentration at admission before labour does not predict severe postpartum haemorrhage in a general obstetric population. Fibrinogen concentration does not decrease significantly during normal labour. Excessive postpartum bleeding is mainly as a result of obstetric complications.