Identifying postpartum depression: Using key risk factors for early detection.

Background: Personal and family history of psychiatric disorders are key risk factors for postpartum depression (PPD), yet their combined contribution has been understudied.

Objective: To examine personal and family psychiatric history, alone and combined, and their effect on absolute risk and relative risk (RR) of mild/moderate or severe PPD.

Methods: In this cohort study, we used data from 142 064 childbirths with PPD screenings from 2015 to 2021 merged with population registers. Exposures were personal and family psychiatric history defined as a psychiatric hospital contact or psychotropic prescription fills by index mothers and their parents prior to delivery. Outcomes were mild/moderate PPD (Edinburgh Postnatal Depression Scale, cut-off: ≥11 within 12 weeks post partum) and severe PPD (antidepressant fill or depression diagnosis within 6 months post partum). We calculated absolute risks and RRs using Poisson regression models adjusted for parity, education, maternal age, and calendar year.

Findings: Of the 142 064 participants, 23.4% had no psychiatric history, 47.4% had only family history, 6.0% had only personal history, and 23.2% had both. The latter group had the highest risk of PPD: absolute risk of mild/moderate PPD was 11.7% (95% CI 11.5%; 11.8%), and adjusted RR: 2.35 (95% CI 2.22; 2.49). Alone, personal psychiatric history was the most potent risk factor. Dose-response relationship based on severity of personal and family psychiatric history was found.

Discussion: Our study documents a substantial association between personal and family psychiatric history and PPD risk.

Clinical implications: Evaluating combinations of risk factors is important to improve risk assessment.