Risk Factors for Secondary Postpartum Haemorrhage: A Retrospective Study

Background: Secondary Postpartum Haemorrhage (SPPH) refers to any abnormal vaginal bleeding between 24 hours to 6 weeks postpartum. SPPH is a relatively unexplored issue and there is limited evidence, especially regarding risk factors. The aim of this study was to identify risk factors for SPPH.. Method: Patients readmitted with a diagnosis of SPPH between 2014 and 2018 at a tertiary hospital in Queensland, Australia were identified. These patients were compared with randomly selected controls that gave birth via vaginal delivery and caesarean section at the centre during the same time period. Logistic regression analyses were applied for categorical variables and T-test along for continuous variables. Result: 110 cases of SPPH were identified and 225 patients that did not have SPPH were randomly allocated as controls. Incomplete placenta (p=0.005), Antepartum Haemorrhage (APH) (p=<0.00), antepartum (p=0.004) anticoagulation, along with previous obstetric complications (p=0.036) were found to be statistically significant risk factors for SPPH. Previous obstetric complications include conditions such as primary PPH, gestational diabetes and pre-eclampsia. Demographic factors of age and ethnicity did not express any predisposition to SPPH along with other factors such as BMI, parity and plurality. The average estimated blood loss within 24 hours of delivery in the SPPH case group was 350ml and control group was 300ml (p=0.038). Conclusion: This study confirms that incomplete placenta, APH, antepartum anti-coagulation and previous obstetric complications are risk factors for secondary postpartum haemorrhage. Early identification of these risk factors could potentially prevent SPPH, allowing a safer postnatal journey for mothers.