Frequently Asked Questions

Postpartum depression was common: 2,469 of 6,552 patients (37.7%) had either a positive postpartum depression screen or a depression ICD diagnosis within 365 days after delivery. The study population included adults with a live birth who had a depression or postpartum depression diagnosis in the year before their last menstrual period and had filled an adequately dosed antidepressant in the 6 months before that date.

Yes. Among patients who already had a history of depression, those with a prior postpartum depression history had a 31% higher adjusted risk of postpartum depression than those with depression history alone (aRR = 1.31; 95% CI, 1.21–1.41).

Yes. In this cohort, stopping an antidepressant during pregnancy was associated with a higher risk of postpartum depression overall (aRR = 1.14; 95% CI, 1.08–1.20) and a higher risk of severe postpartum depression symptoms (aRR = 1.28; 95% CI, 1.01–1.49). Pregnancy antidepressant use was classified from medication fills during pregnancy using a 42-day permissible gap.

Early depressive symptoms were strongly associated with later postpartum depression, and risk increased across symptom severity categories. Compared with a first prenatal PHQ-9 score below 5, mild symptoms (PHQ-9 5–9) were associated with aRR = 1.39 (95% CI, 1.29–1.50) for any postpartum depression and aRR = 1.49 (95% CI, 1.20–1.85) for severe postpartum depression.

Risk remained elevated for higher symptom levels: moderate symptoms (PHQ-9 10–14) had aRR = 1.70 (95% CI, 1.56–1.85) for any postpartum depression and aRR = 2.37 (95% CI, 1.87–3.00) for severe postpartum depression; moderate-severe symptoms (PHQ-9 15–19) had aRR = 1.92 (95% CI, 1.73–2.13) for any postpartum depression and aRR = 3.58 (95% CI, 2.77–4.61) for severe postpartum depression; severe symptoms (PHQ-9 20–27) had aRR = 1.70 (95% CI, 1.56–1.85) for any postpartum depression and aRR = 2.37 (95% CI, 1.87–3.00) for severe postpartum depression.

Yes. Compared with patients identifying as White, adjusted risk of postpartum depression was higher in patients identifying as Black (aRR = 1.21; 95% CI, 1.08–1.36), Asian/Pacific Islander (aRR = 1.17; 95% CI, 1.05–1.30), and LatinX (aRR = 1.16; 95% CI, 1.07–1.25). Risk of severe postpartum depression was also higher in these groups: Black aRR = 1.65 (95% CI, 1.25–2.17), Asian/Pacific Islander aRR = 1.54 (95% CI, 1.18–2.01), and LatinX aRR = 1.29 (95% CI, 1.06–1.58).

Yes. Compared with median neighborhood income over $120,000, patients from neighborhoods with incomes of $60,000–$120,000 had higher adjusted risk of postpartum depression overall (aRR = 1.09; 95% CI, 1.02–1.18) and severe postpartum depression (aRR = 1.31; 95% CI, 1.06–1.62). Patients from neighborhoods with incomes below $60,000 also had higher risk overall (aRR = 1.15; 95% CI, 1.04–1.27) and for severe postpartum depression (aRR = 1.33; 95% CI, 1.02–1.73).

Medicaid insurance was also associated with higher postpartum depression risk overall compared with non-Medicaid insurance (aRR = 1.09; 95% CI, 1.02–1.28).

Yes. Higher antidepressant dosing before the last menstrual period was associated with a higher adjusted risk of postpartum depression overall (aRR = 1.15; 95% CI, 1.03–1.28) and severe postpartum depression (aRR = 1.34; 95% CI, 1.02–1.76).

Yes. Higher parity was associated with lower postpartum depression risk compared with being nulliparous. Patients with parity of 1 had aRR = 0.90 (95% CI, 0.84–0.98), and patients with parity of 2 or more also had aRR = 0.90 (95% CI, 0.83–0.99).

No significant association was found for these factors in this study. Age was not significantly associated with postpartum depression risk, there were no significant age interactions, multiple gestation was not associated with risk, and starting prenatal care after the first trimester was also not associated with postpartum depression risk after adjustment for other factors.

The study defined postpartum depression as both a postpartum PHQ-9 score of 10 or higher after delivery and a depression diagnosis based on ICD-9 or ICD-10 codes. The outcome window extended from birth through 365 days postpartum, and the highest PHQ-9 score during that period was used.

This was a retrospective electronic health record study from Kaiser Permanente Northern California. It included 6,552 patients aged 18 years or older with a live birth between 2010 and 2019 who had a depression or postpartum depression ICD diagnosis in the year before their last menstrual period and had filled an adequately dosed antidepressant in the 6 months before that date.

The health system performed universal depression screening with the PHQ-9 twice during pregnancy and at the first postpartum visit, with more than 98% of perinatal members screened. Associations with postpartum depression were estimated using modified Poisson regression adjusted for demographic, pregnancy, and clinical covariates, including perinatal antidepressant use.

The main limitations are that the study used retrospective electronic health record data and may not fully capture changes in clinical variables over time. The authors also could not assess psychosocial stressors such as lack of social support, intimate partner violence, or other pregnancy-related stressors, and they did not fully characterize prepregnancy depression history with measures such as longitudinal PHQ-9 scores, treatment duration, or complete psychiatric history.

In addition, the cohort was drawn from an integrated health system with routine screening and insurance coverage, so applicability may be limited for populations without similar access to care. The cohort definition also required both a recent depression-related diagnosis and adequate antidepressant use before pregnancy, which may limit generalizability to patients treated with lower antidepressant doses.