This book first assesses the prevalence of vitamin D deficiency and summarizes published randomized controlled studies concerning the supplementation of vitamin D in pregnant women, reporting on the maternal and neonatal outcomes in Asia-Pacific, the United States, Europe, Africa, and the rest of world. The functions of vitamin K and D are discussed, along with the links between the two vitamins, providing insight on the underlying mechanisms responsible for their role in osteosarcoma and identify future perspectives. The closing study highlights the vitamin K-dependent biological pathways which are associated with the prevention and treatment of bone metabolism disorders.