There is a growing realization that efforts to optimize the health of women and reduce the risk of adverse maternal, perinatal and neonatal outcomes during pregnancy should commence in the preconception period. The preconception period (prior to or between pregnancies) provides an opportune time to address reproductive intentions and promote and support wellbeing and healthy behavior change regardless of pregnancy intention. Research over the last 30 years has explored the influence of a range of preconception risk factors and determinants of health on pregnancy and maternal and neonatal outcomes including: pregnancy planning, diet and micronutrient supplementation, physical activity, weight, smoking, recreational drug and alcohol use, mental health, oral hygiene, and chronic health and medical conditions. Preconception health messages, recommendations and guidelines originated in the USA and the preconception movement has gained momentum internationally with a variety of strategies developed and tested for improving preconception health, and related outcomes. The shift to integrate preconception health promotion into the continuum of women's healthcare requires a diverse multilevel and multistrategic approach involving a range of sectors and health professionals to address the determinants of health. This includes a system-wide effort to raise awareness of the importance of women's health prior to pregnancy, creating supportive environments as well as optimizing clinical practice, policy and programs informed by high quality research and longitudinal studies. While preconception health is relevant to both women and men globally, this review summarizes the predominant areas of preconception health for women in developed countries including the emergence of preconception health, the current health messages and evidence, the state of international guidelines and evidence-based interventions in preconception.