Antepartum insomnia symptoms and its association with postpartum depression symptoms in women with and without psychiatric vulnerability: A prospective cohort study.

Background: Postpartum depression is common and may be linked to antepartum insomnia, a potentially modifiable risk factor. We examine the association between insomnia- and postpartum depression symptoms, considering whether psychiatric vulnerability moderates this link.

Method: Participants completed the Insomnia Severity Index during trimester two and three and the Hospital Anxiety and Depression questionnaire postpartum. Linear regression analyses were used to investigate the associations between antepartum insomnia- and postpartum depression symptoms. We used stratified regression models and a test for multiplicative interaction to understand if psychiatric vulnerability moderates this association.

Results: A total of 217 women participated (median age 37, IQR 5). Women with clinically significant insomnia symptoms in trimester two and three reported higher postpartum depression symptoms (p = .008 and p = .002 respectively). Linear regression analyses showed effect sizes that were almost equal for both trimesters (two: β = 0.19, 95 % CI -0.20., 0.40, p = .069 and three: β = 0.23, 95 % CI 0.09., 0.36, p ≤ .001), but only statistically significant for trimester three. When antepartum depression was taken into account, neither the second nor third trimester was significantly associated with postpartum depressive symptoms. Psychiatric vulnerability did not moderate the relationship (p = .163).

Conclusion: Insomnia symptoms in the second and third trimesters are not associated with postpartum depression when antepartum depression is taken into account in both women with and without psychiatric vulnerability. Hence it is important to screen for both insomnia and depression during pregnancy to prevent postpartum depression in all pregnant women.