title: Diagnosis of gestational diabetes mellitus: falling through the net.
abstract: OBJECTIVE
  Gestational diabetes mellitus (GDM) is associated with increased risks to mother and child, but globally agreed diagnostic criteria remain elusive. Identification of women with GDM is important, as treatment reduces adverse outcomes such as perinatal death, shoulder dystocia and neonatal hypoglycaemia. Recently, the UK's National Institute for Health and Care Excellence (NICE) recommended new diagnostic thresholds for GDM which are different from the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criteria endorsed by the WHO. The study aim was to assess neonatal and obstetric outcomes among women who would test positive for the IADPSG criteria but negative for the NICE 2015 criteria.
  
  
  METHODS
  Data from 25,543 consecutive singleton live births (2004-2008) were obtained retrospectively from hospital records. Women were screened with a random plasma glucose (RPG; 12-16 weeks) and a 50 g glucose challenge test (GCT; 26-28 weeks). If RPG >7.0 mmol/l, GCT >7.7 mmol/l or symptoms were present, a 75 g OGTT was offered (n = 3,848).
  
  
  RESULTS
  In this study, GDM prevalence was 4.13% (NICE 2015) and 4.62% (IADPSG). Women who 'fell through the net', testing NICE-negative but IADPSG-positive (n = 387), had a higher risk of having a large-for-gestational-age (LGA) infant (birthweight >90th percentile for gestational age; adjusted OR [95% CI] 3.12 [2.44, 3.98]), Caesarean delivery (1.44 [1.15, 1.81]) and polyhydramnios (6.90 [3.94, 12.08]) compared with women with negative screening results and no OGTT (n = 21,695). LGA risk was highest among women with fasting plasma glucose 5.1-5.5 mmol/l (n = 167): the mean birthweight was 350 g above that of the reference population and 37.7% of infants were LGA.
  
  
  CONCLUSIONS
  The IADPSG criteria identify women at substantial risk of complications who would not be identified by the NICE 2015 criteria.
authors.affiliation: The Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, UK, clm70@cam.ac.uk.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Meek
authors.forename: Hannah B
authors.initials: HB
authors.lastname: Lewis
authors.forename: Charlotte
authors.initials: C
authors.lastname: Patient
authors.forename: Helen R
authors.initials: HR
authors.lastname: Murphy
authors.forename: David
authors.initials: D
authors.lastname: Simmons
mesh_terms: D000328:Adult; D001724:Birth Weight; D001786:Blood Glucose / Q000032:analysis; D002585:Cesarean Section; D016640:Diabetes, Gestational / Q000175:diagnosis*; D005260:Female; D005320:Fetal Macrosomia / Q000175:diagnosis; D005951:Glucose Tolerance Test; D006801:Humans; D007231:Infant, Newborn; D009774:Obstetrics / Q000379:methods; D016017:Odds Ratio; D011247:Pregnancy; D011256:Pregnancy Outcome; D015995:Prevalence; D012189:Retrospective Studies
chemical_list: D001786:Blood Glucose