Nickan Research Institute Journal of Parathyroid Disease 2345-6558 8 1 2020 01 01 An ecological study on distribution of vitamin D level among pregnant women of Iran e04 e04 EN Soheila Akbari Faezeh Salehinasab Seyyed Ezatollah Rafiee Alavi https://orcid.org/0000-0003-0146-9751 Journal Article 2019 08 15 2019 12 27 Introduction: Vitamin D3 is a hormone that acts as immune modulator. Vitamin D deficiency is associated with pregnancy complications such as preeclampsia. Therefore vitamin D deficiency is important in pregnant women. Objectives: This study is designed to investigate ecological distribution of 25-hydroxy vitamin D (25-OHD) level in the Iranian pregnant women. Materials and Methods: The present s is an ecological study based on the geographical information presented in previous papers. Ecological map is designed according to northing (X) and easting (Y) of each individual location as well as 25-OHD level as the depth (Z) of the map. Results: A total of 17 studies were selected from 2005 to 2016. The contour plot showed that eastern and north eastern areas of Iran had higher levels of 25-OHD whereas western and north western areas of Iran showed lower levels of 25-OHD. Around 49.72% of the total area of Iran showed 25-OHD level less than 21.09 ng/mL, 81.91% of the total area showed 25-OHD level less than 25.54 ng/ mL and 96.51% of the total area showed 25-OHD level less than about 29.98 ng/mL. Conclusion: This ecological study with a novel statistical methodology showed that mean of 25-OHD level in pregnant women was less than about 30 ng/mL in more than 96% of the total area of Iran. Because of the association of vitamin D level with pregnancy complications, surveillance interventions are necessary to change the current status.