In the United States, more than half a million women experience postpartum depression every year; among teens and low-income mothers, the rate is one in four. For many depressed mothers, symptoms begin during pregnancy and may also include disabling anxiety. In addition, maternal mental illness adversely affects infant brain development and subsequent social and emotional health as a result of inadequate prenatal care, poor birth outcomes, and impaired parenting practices. The broad implications of these disorders have led several states to require perinatal depression screening and/or education. Also, a provision of the U.S. Affordable Care Act calls for further research on screening and treatment. These policies are a good start, but laws already on the books must be adequately funded and evaluated. In addition, there are immediate policy actions that can be taken to improve the well-being of mothers and families.