These guidelines provide recommendations on action and research for a) preventing early pregnancy: by preventing marriage before 18 years of age; by increasing knowledge and understanding of the importance of pregnancy prevention; by increasing the use of contraception; and by preventing coerced sex; and b) preventing poor reproductive outcomes: by reducing unsafe abortions; and by increasing the use of skilled antenatal, childbirth and postnatal care. These guidelines are primarily intended for policy-makers, planners and program managers from governments, nongovernmental organizations and development agencies. They are also likely to be of interest to public health researchers and practitioners, professional associations and civil society organizations. They have been developed through systematic review of the evidence and technical expertise of policy-makers, program managers and front-line workers from countries around the world, in partnership with many key international organizations working in this field.