title: Measuring glycated haemoglobin in women with gestational diabetes mellitus: How useful is it?
abstract: BACKGROUND
  Glycated haemoglobin (HbA1c) is an important tool for assessing glycaemic status in patients with diabetes, but its usefulness in gestational diabetes mellitus (GDM), is unclear.
  
  
  OBJECTIVE
  The aim of this study is to evaluate whether HbA1c in women with GDM is valuable in predicting adverse pregnancy outcomes.
  
  
  METHODS
  A retrospective review of women with GDM who had HbA1c measured at diagnosis of GDM (GHb-diag) and at 36 weeks gestation (GHb-36 weeks) was conducted. The association between HbA1c and various pregnancy outcomes was assessed RESULTS: Among 1244 women with GDM in our cohort, both GHb-diag and GHb-36 weeks were independent predictors for large-for-gestation (LGA) babies (OR 1.06, P = 0.005 and OR 1.06, P = 0.002, respectively) and neonatal hypoglycaemia (OR 1.10, P < 0.001 and OR 1.09, P < 0.001, respectively). Women with HbA1c ≥ 5.4% (35 mmol/mol) at diagnosis had significantly greater risk for LGA (15.3% vs 8.2%, P < 0.001) and neonatal hypoglycaemia (42.2% vs 23.6%, P < 0.001) than those below this cut-off. The difference between GHb-diag and GHb-36 weeks was small and improvement in HbA1c by 36 weeks was not associated with better pregnancy outcomes.
  
  
  CONCLUSIONS
  We showed that measurement of HbA1c, either at the time of diagnosis of GDM or toward the end of pregnancy, were both associated with adverse pregnancy outcomes. Women with elevated HbA1c (>5.4% or 35 mmol/mol) at diagnosis of GDM should be monitored closely during pregnancy. However, there is not enough evidence to suggest that repeating HbA1c toward the end of pregnancy will provide additional information in predicting adverse pregnancy outcomes.
authors: Liverpool Diabetes Collaborative Research Unit, Ingham Institute of Applied Science, Liverpool, New South Wales, Australia.|South Western Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia.
authors: Vincent W
authors: VW
authors: Wong
authors: South Western Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia.|Epidemiology Group, Healthy People and Places Unit, South Western Sydney Local Health District, Liverpool, New South Wales, Australia.
authors: Shanley
authors: S
authors: Chong
authors: South Western Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia.
authors: Sahil
authors: S
authors: Mediratta
authors: Epidemiology Group, Healthy People and Places Unit, South Western Sydney Local Health District, Liverpool, New South Wales, Australia.|Ingham Institute, University of New South Wales, Liverpool, New South Wales, Australia.
authors: Bin
authors: B
authors: Jalaludin
mesh_terms: D000328:Adult; D016640:Diabetes, Gestational / Q000097:blood* / Q000175:diagnosis; D005260:Female; D005320:Fetal Macrosomia / Q000097:blood / Q000209:etiology*; D005865:Gestational Age; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000209:etiology*; D007231:Infant, Newborn; D011237:Predictive Value of Tests; D011247:Pregnancy; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: gestational diabetes mellitus; glycaemic control; glycated haemoglobin; large-for-gestational age; pregnancy outcomes