Oral Presentation Australasian Diabetes in Pregnancy Society and Society of Obstetric Medicine Australia and New Zealand Joint Scientific Meeting 2021

Early pregnancy glycated haemoglobin identifies Australian Aboriginal women with high-risk of gestational diabetes mellitus and adverse perinatal outcomes (#30)

Emma L Jamieson 1 , Erica P Spry 2 3 , Andrew B Kirke 1 , Emma Griffiths 3 , Carly Roxburgh 4 , Cynthia Porter 5 , Sally Singleton 3 , Kylie Sterry 6 , David N Atkinson 3 , Julia Marley 2 3
  1. The Rural Clinical School of WA, The University of Western Australia, Bunbury, WA, Australia
  2. Kimberley Aboriginal Medical Services, Broome, WA, Australia
  3. The Rural Clinical School of WA, The University of Western Australia, Broome, WA, Australia
  4. The Rural Clinical School of WA, The University of Western Australia, Albany, WA, Australia
  5. Geraldton Regional Aboriginal Medical Service, Geraldton, WA, Australia
  6. The Rural Clinical School of WA, The University of Western Australia, Kalgoorlie, WA, Australia

OBJECTIVE: To assess whether an early pregnancy glycated haemoglobin (HbA1c) can predict subsequent gestational diabetes mellitus (GDM) and adverse birth outcomes in Australian women.

RESEARCH DESIGN AND METHODS: Prospective study of women aged over 16-years, without confirmed diabetes, with first antenatal visit before 20-weeks gestation. Recruitment was from 27 primary health care sites in rural and remote Australia from 9-January 2015 to 31-May 2018. HbA1c was measured with first antenatal investigations (<20-weeks gestation) and compared to routine 75 g oral glucose tolerance test (OGTT; ≥24-weeks gestation) and birth weight for gestational age. Primary outcome measure was predictive value of early HbA1c for GDM and large-for-gestational-age (LGA) newborn.

RESULTS: Of 466 women with an early HbA1c, 396 (129 Aboriginal) had a routine OGTT with 28.8% GDM incidence (24.0% Aboriginal). HbA1c ≥5.6% (≥38 mmol/mol) was highly predictive (71.4%, 95% CI; 47.8-88.7%) for GDM in Aboriginal women, and in the total cohort increased risk for LGA newborn compared to women below this threshold and without GDM (RR 2.04, 95% CI; 1.03-4.01, P=0.040). There were clear differences between groups, with 16.3% of Aboriginal women having early elevated HbA1c and another 12.4% developing hyperglycaemia during pregnancy, compared to only 5.2% and 29.6%, respectively for non-Aboriginal women.

CONCLUSIONS: Early pregnancy HbA1c ≥5.6% (≥38 mmol/mol) appears to identify Aboriginal women who had hyperglycaemia prior to pregnancy (apparent prediabetes) and elevated risk of having an LGA newborn. Universal HbA1c at first antenatal presentation could lead to earlier management of hyperglycemia and improved perinatal outcome in this high-risk population.