Clinical problems due to vitamin D deficiency, such as rickets and osteomalacia, are still important despite the improvement in public health. Within the last two decades, attention has remained focused on vitamin D deficiency as being a common problem for both mother and fetus (baby). Therefore, the definition of “perinatal vitamin D deficiency” has become a more significant issue. Maternal vitamin D deficiency is the most important risk factor for rickets in neonates and early infancy. On the other hand, in terms of extraskeletal effects, the results of vitamin D deficiency during pregnancy may continue lifelong. Vitamin D supplementation from the first days of life with 400 U/ day is common, but adequate supplementation for pregnants (2000 U/day) is usually not administered. The campaign of free vitamin D for all babies is very effective in our country; however, there is a need of expansion in this campaign to cover pregnants in order to prevent maternal/perinatal vitamin D deficiency. Anahtar Kelimeler : D vitamini, fetus, gebe, yenidoğan.