Mental illness affects up to 20 % of women of reproductive age. Maternal mental illness pre-pregnancy and/or during pregnancy is an independent risk factor for prematurity, stillbirth and small for gestational age. Data on maternal mental illness and other birth outcomes are mixed. There are several different screening tools available to identify mothers with mental illness. Although the timing of screening varies among providers, antenatal screening provides more opportunities to identify and support mothers with mental illness. If identified prior to potential maternal mental illness exacerbations complicating decision-making capacity there may be an opportunity for advanced directives. This review focuses on the impact of maternal mental illness on delivery mode and timing, birth outcomes, and breastfeeding. We discuss maternal mental illness screening tools, relevant benefits and disadvantages as well as timing and location (obstetric and pediatric settings). Finally, ethical and policy implications are detailed.