title: Vitamin D and gestational diabetes: an update.
abstract: OBJECTIVE
  Vitamin D status (which is involved in glucose homeostasis) is related to gestational diabetes mellitus (GDM). GDM is characterized by increased resistance to and impaired secretion of insulin and results in higher risk of adverse pregnancy outcomes including operative delivery, macrosomia, shoulder dystocia and neonatal hypoglycemia. Women with GDM and their babies are at increased risk for developing type II diabetes.
  
  
  RESULTS
  International definitions of vitamin D deficiency and normality are inconsistent. Vitamin D deficiency is common in pregnant women particularly those with poor diets and who have dark skins living in temperate climes with lack of exposure to sunlight.
  
  
  CONCLUSIONS
  Few interventional studies indicate that supplementation optimizes maternal vitamin D status or improves maternal glucose metabolism. Observational studies about maternal vitamin D status and risk of GDM are conflicting. This could be because of measurement of vitamin D or differences in population characteristics such as ethnicity, geographic location, gestational age at sampling and diagnostic criteria for GDM. Good-quality randomized controlled trials are required to determine whether vitamin D supplementation decreases the risk of GDM or improves glucose tolerance in diabetic women.
authors.affiliation: aDepartment of Gynecology and Obstetrics, Clinical Institute, University of Southern Denmark, Odense University Hospital, Odense, Denmark bDivision of Surgery, University College, London, Northwick Park Institute of Medical Research Campus, London, UK cBrazilian Cochrane Centre dDepartment of Internal Medicine, São Paulo Federal University, São Paulo, Brazil.
authors.forename: Jan S
authors.initials: JS
authors.lastname: Joergensen
authors.forename: Ronald F
authors.initials: RF
authors.lastname: Lamont
authors.forename: Maria R
authors.initials: MR
authors.lastname: Torloni
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D016640:Diabetes, Gestational / Q000097:blood* / Q000209:etiology / Q000517:prevention & control; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D009752:Nutritional Status; D064887:Observational Studies as Topic; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications / Q000188:drug therapy
chemical_list: D007328:Insulin; D014807:Vitamin D