This study examines the association between perinatal depression (PND) and the risk of suicidal behavior, including suicide attempts and completed suicide, among women. Conducted in Sweden, the study included 86,551 women with PND and 865,510 unaffected women matched on age and calendar year at delivery. The follow-up period was up to 18 years. Key findings include: - Women with PND had a 3.15 times higher risk of suicidal behavior compared to matched unaffected women (95% CI 2.97-3.35). - The excess risk was particularly high within the first year after PND diagnosis (HR 7.20, 95% CI 6.07-8.54) and remained elevated over 18 years (HR 2.34, 95% CI 2.12-2.57). - The association was more pronounced among women without a history of psychiatric disorders. - Postnatal depression was associated with a higher risk of suicidal behavior compared to antenatal depression. - The most common methods of suicidal behavior were poisoning and hanging, with hanging showing the strongest association (HR 7.29, 95% CI 4.42-12.03). The study highlights the need for vigilant clinical monitoring and interventions for women with PND to prevent suicidal outcomes, regardless of their history of psychiatric disorders.This study examines the association between perinatal depression (PND) and the risk of suicidal behavior, including suicide attempts and completed suicide, among women. Conducted in Sweden, the study included 86,551 women with PND and 865,510 unaffected women matched on age and calendar year at delivery. The follow-up period was up to 18 years. Key findings include: - Women with PND had a 3.15 times higher risk of suicidal behavior compared to matched unaffected women (95% CI 2.97-3.35). - The excess risk was particularly high within the first year after PND diagnosis (HR 7.20, 95% CI 6.07-8.54) and remained elevated over 18 years (HR 2.34, 95% CI 2.12-2.57). - The association was more pronounced among women without a history of psychiatric disorders. - Postnatal depression was associated with a higher risk of suicidal behavior compared to antenatal depression. - The most common methods of suicidal behavior were poisoning and hanging, with hanging showing the strongest association (HR 7.29, 95% CI 4.42-12.03). The study highlights the need for vigilant clinical monitoring and interventions for women with PND to prevent suicidal outcomes, regardless of their history of psychiatric disorders.