Ineffective management of blood glucose levels during preconception and pregnancy has been associated with severe maternal and fetal complications in women with pre-existing diabetes. Studies have demonstrated that preconception counseling and pre-pregnancy care can dramatically reduce these risks. However, pregnancy-related outcomes in women with diabetes continue to be less than ideal. This review highlights and discusses a variety of patient, provider, and organizational factors that can contribute to these suboptimal outcomes. Based on the findings of studies reviewed and authors' clinical and research experiences, recommendations have been proposed focusing on various aspects of care provided, including improved accessibility to effective preconception and pregnancy-related care and better organized clinic consultations that are sensitive to women's diabetes and pregnancy needs.