title: Screening for gestational diabetes: a summary of the evidence for the U.S. Preventive Services Task Force.
abstract: OBJECTIVE
  To systematically review the evidence for screening for gestational diabetes mellitus (GDM).
  
  
  METHODS
  We established eligibility criteria for relevant studies. We systematically searched MEDLINE and the Cochrane Collaboration Library for studies meeting eligibility criteria. We supplemented this search with further studies identified from reference lists of reviews.
  
  
  METHODS
  Two reviewers examined each article for eligibility. A single reviewer abstracted relevant data from the included articles; a second reviewer checked the abstractions. We graded the quality of the articles according to criteria developed by the U.S. Preventive Services Task Force.
  
  
  RESULTS
  No well-conducted, randomized, controlled trial provides direct evidence for the health benefits of screening for GDM. The evidence is unclear regarding the optimal screening and reference diagnostic test for GDM. The impact of hyperglycemia on adverse maternal and neonatal health outcomes is probably continuous. Although insulin therapy decreases the incidence of fetal macrosomia for those women with more severe degrees of hyperglycemia, the magnitude of any effect on maternal and neonatal health outcomes is not clear. The evidence is insufficient to determine the magnitude of health benefit for any treatment among the large number of women with GDM at milder degrees of hyperglycemia. We found limited evidence regarding the potential adverse effects of screening for GDM.
  
  
  CONCLUSIONS
  Because of the lack of high-quality evidence concerning critical issues, we are unable to determine the extent to which screening has an important impact on maternal and neonatal health outcomes. A randomized, controlled trial of screening is necessary to answer the many remaining questions.
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. sbrody@med.unc.edu
authors.forename: Seth C
authors.initials: SC
authors.lastname: Brody
authors.forename: Russell
authors.initials: R
authors.lastname: Harris
authors.forename: Kathleen
authors.initials: K
authors.lastname: Lohr
mesh_terms: D000293:Adolescent; D000328:Adult; D016640:Diabetes, Gestational / Q000453:epidemiology / Q000517:prevention & control*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000592:standards* / Q000639:trends; D008428:Maternal Mortality; D008875:Middle Aged; D011247:Pregnancy; D011256:Pregnancy Outcome; D011295:Prenatal Care / Q000379:methods; D015995:Prevalence; D011322:Primary Prevention / Q000592:standards* / Q000639:trends; D012307:Risk Factors; D014481:United States / Q000453:epidemiology