Factors associated with onset timing, symptoms, and severity of depression identified in the postpartum period

•Postpartum onset of depression is associated with favorable demographic factors.•Mothers with bipolar disorder are at risk for a pre-pregnancy onset and agitation.•Earlier onset of depression is associated with increased severity and chronicity.

BackgroundUnipolar and bipolar depression identified in the postpartum period have a heterogeneous etiology. The objectives of this study are to examine the risk factors that distinguish the timing of onset for unipolar and bipolar depression and the associations between depression onset by diagnosis, and general and atypical depressive symptoms.MethodsSymptoms of depression were assessed at 4- to 6-weeks postpartum by the Structured Interview Guide for the Hamilton Depression Rating Scale-Atypical Depression Symptoms in an obstetrical sample of 727 women. Data were analyzed using ANOVA, Chi-square, and linear regression.ResultsMothers with postpartum onset of depression were more likely to be older, Caucasian, educated, married/cohabitating, have one or no previous child, and have private insurance in contrast to mothers with pre-pregnancy and prenatal onset of depression. Mothers with bipolar depression were more likely to have a pre-pregnancy onset. Three general and two atypical depressive symptoms distinguished pre-pregnancy, during pregnancy, and postpartum depression onset, and the presence of agitation distinguished between unipolar and bipolar depression.LimitationsThe sample was urban, which may not be generalizable to other populations. The study was cross-sectional, which excludes potential late onset of depression (after 4-6 weeks) in the first postpartum year.ConclusionsA collective set of factors predicted the onset of depression identified in the postpartum for mothers distinguished by episodes of unipolar versus bipolar depression, which can inform clinical interventions. Future research on the onset of major depressive episodes could inform prophylactic and early psychiatric interventions.