Vitamin C (VC, L-ascorbic acid) is a water-soluble vitamin that functions as an electron donor to reduce reactive oxygen species such as superoxide and hydroxyl radicals. VC is also a cofactor for numerous biosynthetic enzymes such as prolyl and lysyl hydroxylases for procollagen hydroxylation. VC is synthesized mainly in the liver of most mammalian species including mice and rats. However, humans, primates, and guinea pigs are unable to synthesize VC in vivo. VC is thought to be required for the maintenance of pregnancy and fetal development. However, the effects of an VC's absence on embryonic and neonatal development during pregnancy have not been determined. Therefore, we examined pregnant mice completely or partially deprived of VC to test embryonic and neonatal development by using SMP30/GNL knockout mice which are unable to synthesize VC in vivo. As a result, we found that an absence or a low intake of VC during pregnancy induced multiple abnormalities in the developing tissues of SMP30/GNL knockout mice. In another study, we also found that these SMP30/GNL knockout mice were shorter in life-span than the wild-type mice when fed a VC low diet (about 2.5% a day of VC). Therefore, a diet that supplies an adequate amount of VC is essential to provide optimal conditions for fetal and neonatal health and to avoid a life-shortening deficiency.