Postnatal Depression Beyond 12 Months: A Systematic Review and Meta-Analysis

Area of Science:

• Perinatal Mental Health
• Epidemiology
• Psychiatry

Background:

• Postnatal depression (PND) is traditionally defined as occurring within the first year after childbirth.
• Recent extensions of specialist perinatal mental health services into the second year postpartum necessitate understanding PND prevalence during this period.
• Existing data on PND prevalence beyond 12 months postpartum is limited.

Purpose of the Study:

• To determine the best estimate for the prevalence of postnatal depression (PND) in the second year postpartum (13-24 months).
• To compare the prevalence of PND in the second year postpartum with that in the first year.

Main Methods:

• Systematic review and meta-analysis of studies assessing PND prevalence beyond 12 months postpartum.
• Searches conducted across major databases (PubMed, Embase, Web of Science, CINAHL, PsychINFO) updated in February 2024.
• Included studies using validated screening tools or clinical diagnosis, excluding those with pre-existing depression; quality assessed using ROBINS-I and Risk of Bias 2 tools.

Main Results:

• 32 studies involving 57,210 participants across 18 countries met the inclusion criteria.
• The prevalence of PND in the second year postpartum (13-24 months) was estimated at 15% (95% CI 12%-17%).
• This prevalence is similar to the estimated 16% (95% CI 14%-19%) in the first year postpartum.

Conclusions:

• A significant proportion of women experience postnatal depression (PND) in the second year after birth.
• The prevalence of PND in the second year postpartum is comparable to that in the first year.
• Findings support the extension of perinatal mental health services and monitoring for PND beyond the initial 12 months postpartum.