[Influence of vitamin D on fertility and fetal development--review of literature].

Cholecalciferol was qualified by FDA (Food and Drug Administration) into the A category if administered in recommended doses and to the D category if the doses exceed RDA (Recommended Dietary Allowance). There are very divergent opinions among researchers concerning the optimal daily dose of vitamin D-according to some of them, the optimal dose of vitamin D should exceed 400 Ul/24h. On the other hand, there is no data to estimate the optimal dose and to formulate recommendations. It is necessary to conduct research on animal models to fully comprehend the symptoms and syndromes caused by excess or deficiency of cholecalciferol. However, the conclusions of the research done on animals should not be over-generalized. Moreover, some data concerning the influence of vitamin D administered during the pregnancy on fetal development are often ambiguous. All these facts are the reason why recommendations of vitamin D supplementation in pregnancy still remain uncertain and need thorough investigation.