ROXANA ELENA BOHILTEA, CORINA-AURELIA ZUGRAVU, ADRIAN NEACSU, DAN NAVOLAN, COSTIN BERCEANU, DRAGOS NEMESCU, OANA BODEAN, NATALIA TURCAN, ALEXANDRU BAROS, MONICA MIHAELA CIRSTOIU THE PREVALENCE OF VITAMIN D DEFFICIENCY AND ITS OBSTETRICAL EFFECTS A PROSPECTIVE STUDY ON ROMANIAN PATIENTS The birth, growth, development, reproduction and senescence under physiological conditions can be achieved without diminishing the role of other important aspects that influence them, only with the support of an optimal diet that is a fundamental requirement nowadays, considering that the health and the nutritional status are in a permanent interdependence. The effects of inadequate nutrition reflect on the expression of genes, influencing the development of certain diseases in childhood and adulthood. Knowing the phases of the gestation period in which the need of certain nutrients is increased, and their absence has the most serious impact on fetal growth and development, allows for the adoption in due time of concrete preventive rules. Disorders associated with lipid malabsorption, such as celiac disease, Crohn’s disease, pancreatic insufficiency, cystic fibrosis and cholestatic disease, are associated with low serum levels of 5-hydroxyvitamin D. Vitamin D deficiency in the newborn can express as deficient skeletal homeostasis, congenital rickets and fractures in the early days of life. A low level of vitamin D during pregnancy seems to increase the risk of preeclampsia, intrauterine growth restriction and gestational diabetes, and in the longer term it seems to affect the bone, immune system and general status. The prevalence of hypovitaminosis D is increasing globally, and the effects on pregnancy and neonatal outcome of the vitamin D deficiency and supplementation are a topical issue, which is currently under investigation.