The impact of prenatal maternal depression, during the COVID-19 pandemic on maternal postpartum depression: A prospective cohort study within the conception study

• >40 % of participants reported possible to probable prenatal depression. • Almost 40 % of participants reported possible to probable postpartum depression. • Risk of postpartum depression increased with the severity of prenatal depression. • Risk of postpartum depression increased with prenatal stress and being nulliparous. The COVID-19 pandemic introduced unprecedented disruptions impacting perinatal mental health. We aimed to quantify the association between prenatal depression (PD) and postpartum depression (PPD), within this context. Data were collected from Canadian pregnant individuals (aged≥18) through web-based questionnaires. Individuals who completed both a baseline questionnaire (06/2020 to 12/2021) and the 2-month postpartum follow-up, were included. PD was assessed with the Edinburgh Postnatal Depression Scale (EPDS), categorized as unlikely (EPDS 0–8), possible (9–11), highly possible (12–13), and probable (EPDS≥14). PPD was assessed at 2 months postpartum also using EPDS, and categorized as unlikely (EPDS 0–8), possible to probable (EPDS≥9). Self-reported data on sociodemographics, comorbidities, gestational age, anxiety (General Anxiety Disorder-7), stress, maternal hardship (CONCEPTION Assessment of Stress from COVID-19) were collected. We used a multivariate Poisson regression model to calculate relative risks (RRs) with 95 % confidence interval (CI) to assess the risk of PPD associated with PD. Among 1247 participants, 57.9 % had unlikely PD, 17.1 % possible PD, 9.3 % highly possible PD, 15.7 % probable PD. The overall prevalence of PPD was 39.5 %. Possible PD increased PPD risk (aRR 1.56, 95 % CI 1.18 – 2.05); Highly possible PD further heightened the risk (aRR: 2.24, 95 % CI 1.65 – 3.04); and the highest risk for probable PD (aRR 2.29, 95 % CI 1.66 – 3.15). PPD risk also increased with prenatal stress (aRR 1.07; 95 % CI 1.01 – 1.13) and nulliparity (aRR 1.26, 95 % CI 1.04 – 1.54). Addressing prenatal depression, especially during crises, is crucial to reduce PPD risk and improve maternal and child health.