Background: This study measured antenatal risk factors for postnatal depression in the Australian population, both singly and in combination. Risk factor data were gathered antenatally and depressive symptoms measured via the beyondblue National Postnatal Depression Program, a large prospective cohort study into perinatal mental health, conducted in all six states of Australia, and in the Australian Capital Territory, between 2002 and 2005.
Methods: Pregnant women were screened for symptoms of postnatal depression at antenatal clinics in maternity services around Australia using the Edinburgh Postnatal Depression Scale (EPDS) and a psychosocial risk factor questionnaire that covered key demographic and psychosocial information.
Results: From a total of 40,333 participants, we collected antenatal EPDS data from 35,374 women and 3144 of these had a score >12 (8.9%). Subsequently, efforts were made to follow-up 22,968 women with a postnatal EPDS. Of 12,361 women who completed postnatal EPDS forms, 925 (7.5%) had an EPDS score >12. Antenatal depression together with a prior history of depression and a low level of partner support were the strongest independent antenatal predictors of a postnatal EPDS score >12.
Limitations: The two main limitations of the study were the use of the EPDS (a self-report screening tool) as the measure of depressive symptoms rather than a clinical diagnosis, and the rate of attrition between antenatal screening and the collection of postnatal follow-up data.
Conclusions: Antenatal depressive symptoms appear to be as common as postnatal depressive symptoms. Previous depression, current depression/anxiety, and low partner support are found to be key antenatal risk factors for postnatal depression in this large prospective cohort, consistent with existing meta-analytic surveys. Current depression/anxiety (and to some extent social support) may be amenable to change and can therefore be targeted for intervention.