title: When should screening be performed for gestational diabetes?
abstract: OBJECTIVE
  To consider the arguments for screening outside the standard screening period of 24 to 28 weeks of gestation.
  
  
  METHODS
  A search of the literature between 1990 and 2010 was performed using the PubMed® and Cochrane® databases. Recommendations from learned societies in diabetology and obstetrics & gynaecology were consulted.
  
  
  RESULTS
  Gestational diabetes mellitus screening is classically recommended between weeks 24 and 28 of pregnancy, the period during which glucose tolerance deteriorates. However, the increasing prevalence of type 2 diabetes in women of childbearing age with risk factors requires earlier screening. Fasting blood glucose should be measured at the fi rst visit during early pregnancy for these patients. The diagnostic threshold is the same as for patients who are not pregnant, i.e. blood glucose > 1.26 g/l. However, the benefit of screening for gestational diabetes during early pregnancy for women with risk factors has not been supported by prospective studies. Therefore oral glucose tolerance testing during early pregnancy is not currently recommended for the detection of gestational diabetes. Screening for gestational diabetes, regardless of the recommended screening policy, must be performed between weeks 24 and 28 of pregnancy. There are no reasons to consider subsequent screening for gestational diabetes at a later stage.
authors.affiliation: Service maladies métaboliques et endocriniennes, hôpital Caremeau, CHU de Nîmes, place Pr. Debré, 30900 Nîmes, France.
authors.forename: A-M
authors.initials: AM
authors.lastname: Guedj
mesh_terms: D016640:Diabetes, Gestational / Q000175:diagnosis*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000379:methods*; D012307:Risk Factors