Pregnancy and childbirth can be sources of excitement and joy for many new parents, but for some women, the hormonal fluctuations and lifestyle changes associated with pregnancy and being a new mother can feel overwhelming. Although up to 85 percent of mothers may experience mood changes (sometimes referred to as the "baby blues") for a short period of time after giving birth due to changes in hormone levels, for some women, troubling symptoms may persist for months, warranting a more serious diagnosis of depression. In the 12 months following childbirth, women are 50 percent more likely to experience an episode of major depression. Furthermore, between seven and 12 percent of expectant mothers experience depression at some point during their pregnancy. Depression not only interferes significantly with a mother's mental, physical and emotional well-being, it can have a number of detrimental effects on children's healthy development as well. Efforts to identify and treat maternal depression in its early stages are critical to ensuring the long-term health and safety of Colorado's mothers and their children. "Maternal Depression" is one in a series of six briefs published by the Colorado Children's Campaign addressing maternal and child health topics titled "Healthy Moms, Healthy Kids: A Series on Maternal and Child Health in Colorado". Other topics in the series include domestic violence, maternal depression, healthy pregnancies, family structure and teen motherhood and social determinants of health. (Contains 22 endnotes.)