Longitudinal data from 2002-2013 collected for the International Maternal Pediatric Adolescent AIDS Clinical Trial Network P1025 study were used to examine associations of perinatal depressive symptoms with viral suppression (defined as VL < 400 copies/mL), as well as the degree to which ART adherence might mediate these associations.  Information regarding 1869 participants was included: 77% were diagnosed with HIV before the pregnancy, with an average 5.8 years since diagnosis.  At baseline (third trimester), mean depressive symptom score was 14 (possible total score range 6 to 36—higher scores indicate more symptoms), 68% reported consistent ART adherence, and 77% had achieved viral suppression.  At delivery, average depressive symptom scores declined slightly while levels of adherence and viral suppression steadily increased.  However, although depressive symptoms continued to decline postpartum, adherence and viral suppression levels fell sharply (from 69.5% and 74.4% at delivery to 59.8% and 53% at 6 months postpartum).  Smoking and alcohol use declined towards delivery but increased substantially postpartum.  Investigators observed that a relatively moderate increase in depressive symptoms was associated with a potentially clinically important decline in viral suppression and ART adherence: the decline in adherence driven by depressive symptoms accounted for ~11% of the total negative effect of depressive symptoms on viral suppression.