title: Women with an HbA1c of 41-49 mmol/mol (5.9-6.6%): a higher risk subgroup that may benefit from early pregnancy intervention.
abstract: OBJECTIVE
  To examine whether women with an HbA1c of 41-49 mmol/mol (5.9-6.6%) at diagnosis of gestational diabetes are higher risk than women with an HbA1c of < 41 mmol/mol (5.9%) and whether pregnancy outcomes are improved if treated at < 24 weeks' gestation.
  
  
  METHODS
  This was an observational study of women with gestational diabetes diagnosed by early HbA1c screening or subsequent oral glucose tolerance test at < 34 weeks' gestation who delivered at National Women's Health, Auckland, from July 2012 to June 2014. Data were extracted from the hospital database. Women with HbA1c 41-49 mmol/mol (5.9-6.6%) were divided into those seen < 24 weeks (Early, n = 134) and those seen ≥ 24 weeks (Later, n = 151). Those with HbA1c < 41 mmol/mol (5.9%) were labelled Other GDM (n = 661).
  
  
  RESULTS
  The Early and Later groups, compared with Other GDM, had more Polynesian and fewer (non-Indian) Asian women, higher BMI and more required medication (P < 0.001). More were smokers (P = 0.007, 0.02) and more had chronic hypertension (P < 0.001, 0.02). There were higher rates of adverse outcomes in the Later group than the Other GDM group (pre-eclampsia 8.0% vs. 2.4%, P = 0.001, preterm birth 16.6% vs. 8.2%, P = 0.002, neonatal admission 15.5% vs. 9.2%, P = 0.02). Outcomes were similar between the Early group and Other GDM group (pre-eclampsia 1.5% vs. 2.4%, P = 0.5, preterm birth 10.5% vs. 8.2% P = 0.4, neonatal admission 13.6% vs. 9.2%, P = 0.12). Comparing the Early and Later groups, the Early group had less pre-eclampsia, 1.5% vs. 8.0%, adjusted P = 0.03. Other outcomes were not statistically different.
  
  
  CONCLUSIONS
  An HbA1c of 41-49 mmol/mol (5.9-6.7%) identifies a higher-risk group of women with gestational diabetes. Overall, our data support early treatment of women with an HbA1c ≥ 41 mmol/mol (5.9%).
authors.affiliation: Department of Obstetrics and Gynaecology, National Women's Health, Auckland, New Zealand.
authors.forename: J A
authors.initials: JA
authors.lastname: Rowan
authors.affiliation: Department of Obstetrics and Gynaecology, National Women's Health, Auckland, New Zealand.
authors.forename: A
authors.initials: A
authors.lastname: Budden
authors.affiliation: Department of Obstetrics and Gynaecology, National Women's Health, Auckland, New Zealand.
authors.forename: V
authors.initials: V
authors.lastname: Ivanova
authors.affiliation: Department of Obstetrics and Gynaecology, University of Otago, Christchurch Women's Hospital, Christchurch, New Zealand.
authors.forename: R C
authors.initials: RC
authors.lastname: Hughes
authors.affiliation: Department of Obstetrics and Gynaecology, National Women's Health, Auckland, New Zealand.|Department of Epidemiology and Biostatistics, School of Population Health, University of Auckland, Auckland, New Zealand.
authors.forename: L C
authors.initials: LC
authors.lastname: Sadler
mesh_terms: D000328:Adult; D044466:Asian People; D016640:Diabetes, Gestational / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology / Q000628:therapy; D042241:Early Diagnosis; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology / Q000517:prevention & control*; D015931:Intensive Care, Neonatal; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology / Q000517:prevention & control*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk / Q000097:blood* / Q000208:ethnology; D047928:Premature Birth / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control* / Q000628:therapy; D011296:Prenatal Diagnosis; D012307:Risk Factors; D044465:White People
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human