Associations between postpartum haemorrhage, postnatal mental health and longer term mental illness: a record-linked cohort study

Aim To investigate the associations between primary postpartum haemorrhage (PPH), postnatal mental health and longer-term mental illness in a high-income setting. Methods A population-based retrospective cohort study of 18,798 women giving birth between 2008 and 2016 in Grampian, Scotland, was conducted, using linked data from the Aberdeen Maternity and Neonatal Databank and Scottish administrative healthcare datasets. 'Longer-term mental illness' was assessed using a composite outcome comprising mental-health related hospitalisation, prescription or death, from the end of the first postnatal year to 10 years after birth. We used extended Cox regression models to investigate the association between primary PPH in any first or subsequent births (the exposure) and subsequent mental illness, adjusted for sociodemographic, past medical history and pregnancy and birth-related factors, stratified by the presence of mental illness in the first postnatal year. Results We found no association between PPH and longer-term mental illness beyond the first postnatal year, regardless of severity of PPH or mode of birth [adjusted hazard ratio (aHR) 0.97, 95% confidence interval (CI) 0.81-1.16, p = 0.75]. Women who received psychotropic medication, or were hospitalised for mental illness in the first postnatal year, were around 12 times more likely [aHR 12.77,95% CI 10.94-14.91,p < 0.001] to experience mental illness in the second and third postnatal year, with a continuing association for up to 10 years after the first postnatal year, independent of PPH status. Conclusions This study provides no evidence of an association between PPH and longer-term mental illness, after taking into account the presence of mental illness in the first postnatal year.