Is insomnia in late pregnancy a risk factor for postpartum depression/depressive symptomatology?

The aim of the present work was to investigate if insomnia in late pregnancy is a risk factor for postpartum depressive symptomatology/postpartum depression (PPD). 581 women in their last trimester of pregnancy answered questions/questionnaires about lifetime history of insomnia, current sleep perception, current mood and depressive symptomatology. They were interviewed with the Portuguese version of the Diagnostic Interview for Genetic Studies. After delivery 382 (65.7%) mothers participated again in the study. Insomnia in pregnancy was not a risk factor for PPD (DSM-IV or ICD-10) but was a significant predictor of postpartum depressive symptomatology. Negative Affect (NA) was a significant predictor of postpartum depressive symptomatology. Women with higher NA were 4.6 (CI95% = 1.69–12.74) and 5.3 times (CI95% = 2.26–12.58) more likely of experiencing PPD (DSM-IV/ICD-10, respectively) than women with lower NA. Lifetime Depression was a significant predictor of postpartum depressive symptomatology and ICD-10/PPD (OR = 2.6; CI95% = 1.16–4.38). Positive Affect (PA) showed to be a protective factor for postpartum depressive symptomatology and DSM-IV/PPD (OR = 1.5; CI95% = 1.20–2.33). Controlling NA, PA and Lifetime Depression, insomnia lost its predictive role, suggesting these variables might work as mediators. Associations between insomnia, NA, PA and Lifetime Depression should be assessed in pregnancy. This might help to preventively target NA, enhance PA and reduce the likelihood of experiencing postpartum depressive symptomatology.