An Early Pregnancy HbA1c ≥5.9% (41 mmol/mol) Is Optimal for Detecting Diabetes and Identifies Women at Increased Risk of Adverse Pregnancy Outcomes
Abstract
Objective Pregnant women with undiagnosed diabetes are a high-risk group that may benefit from early intervention. Extrapolating from nonpregnancy data, HbA1c ≥6.5% (48 mmol/mol) is recommended to define diabetes in pregnancy. Our aims were to determine the optimal HbA1c threshold for detecting diabetes in early pregnancy as defined by an early oral glucose tolerance test (OGTT) at Research design and methods During 2008-2010 in Christchurch, New Zealand, women were offered an HbA1c measurement with their first antenatal bloods. Pregnancy outcome data were collected. A subset completed an early OGTT, and HbA1c performance was assessed using World Health Organization criteria. Results HbA1c was measured at a median 47 days' gestation in 16,122 women. Of those invited, 974/4,201 (23%) undertook an early OGTT. In this subset, HbA1c ≥5.9% (41 mmol/mol) captured all 15 cases of diabetes, 7 with HbA1c Conclusions HbA1c measurements were readily performed in contrast to the low uptake of early OGTTs. HbA1c ≥5.9% (≥41 mmol/mol) identified all women with diabetes and a group at significantly increased risk of adverse pregnancy outcomes.
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Women with HbA1c ≥ 6.0-6.4% (≥ 42-47 mmol/mol) in early pregnancy have high rates of early gestational diabetes mellitus with a positive predictive value of 54% in a large study from Aotearoa New Zealand.
“Women with HbA1c in this range have high rates of early gestational diabetes mellitus with a positive predictive value of 54% in a large study from Aotearoa New Zealand. 43”
Observational studies demonstrate that intermediate hyperglycaemia (HbA1c ≥ 6.0-6.4% [≥ 42-47 mmol/mol]) is associated with elevated risk of pregnancy complications.
“Observational studies demonstrate that intermediate hyperglycaemia (HbA1c ≥ 6.0‐6.4% [≥ 42–47 mmol/mol]) is associated with elevated risk of pregnancy complications. 43 , 44 , 45 , 46”
Cites
Metzger, B. E., Gabbe, S. G., Persson, B., Lowe, L. P., Dyer, A. R., Oats, J. J. N., & Buchanan, T. A. (2010) · Diabetes Care · doi:10.2337/dc10-0719 · Cited by 1,888 · see citing works
Lawrence, J. M., Contreras, R., Chen, W., & Sacks, D. A. (2008) · Diabetes Care · doi:10.2337/dc07-2345 · Cited by 658 · see citing works
Herman, W. H., Ma, Y., Uwaifo, G., Haffner, S., Kahn, S. E., Horton, E. S., Lachin, J. M., Montez, M. G., Brenneman, T., Barrett-Connor, E., et al. (2007) · Diabetes Care · doi:10.2337/dc06-2003 · Cited by 574 · see citing works
Reference intervals for hemoglobin A1c in pregnant women: data from an Italian multicenter study
Mosca, A., Paleari, R., Dalfrà, M. G., Di Cianni, G., Cuccuru, I., Pellegrini, G., Malloggi, L., Bonomo, M., Granata, S., Ceriotti, F., et al. (2006) · Clinical Chemistry · doi:10.1373/clinchem.2005.064899 · Cited by 161 · see citing works
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2. Classification and Diagnosis of Diabetes: <i>Standards of Medical Care in Diabetes—2022</i>
American Diabetes Association Professional Practice Committee (2022) · Diabetes Care · doi:10.2337/dc22-s002 · Cited by 4,792 · see citing works
Issues with the diagnosis and classification of hyperglycemia in early pregnancy
McIntyre, H. D., Sacks, D. A., Barbour, L. A., Feig, D. S., Catalano, P. M., Damm, P., & McElduff, A. (2016) · Diabetes Care · doi:10.2337/dc15-1887 · Cited by 181 · see citing works
Gestational Diabetes Mellitus and Preeclampsia: Correlation and Influencing Factors
Yang, Y., & Wu, N. (2022) · Frontiers in Cardiovascular Medicine · doi:10.3389/fcvm.2022.831297 · Cited by 155 · see citing works
Brown, F. M., & Wyckoff, J. (2017) · Current Diabetes Reports · doi:10.1007/s11892-017-0922-z · Cited by 122 · see citing works
Role of first trimester HbA1c as a predictor of adverse obstetric outcomes in a multi-ethnic cohort.
Mañé, L., Flores-Le Roux, J. A., Benaiges, D., Rodríguez, M., Marcelo, I., Chillarón, J. J., Pedro-Botet, J., Llauradó, G., Gortazar, L., Carreras, R., et al. (2016) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2016-2581 · Cited by 91 · see citing works
Wexler, D. J., Powe, C. E., Barbour, L. A., Buchanan, T., Coustan, D. R., Corcoy, R., Damm, P., Dunne, F., Feig, D. S., Ferrara, A., et al. (2018) · Obstetrics & Gynecology · doi:10.1097/aog.0000000000002726 · Cited by 80 · see citing works
Self-citationHo, Y.-R., Wang, P., Lu, M.-C., Tseng, S.-T., Yang, C.-P., & Yan, Y.-H. (2017) · PLoS ONE · doi:10.1371/journal.pone.0177563 · Cited by 59 · see citing works
HbA1c Measured in the First Trimester of Pregnancy and the Association with Gestational Diabetes
Hinkle, S. N., Tsai, M. Y., Rawal, S., Albert, P. S., & Zhang, C. (2018) · Scientific Reports · doi:10.1038/s41598-018-30833-8 · Cited by 57 · see citing works
Sweeting, A. N., Ross, G. P., Hyett, J., Molyneaux, L., Tan, K., Constantino, M., Harding, A. J., & Wong, J. (2016) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2016-2951 · Cited by 47 · see citing works
Mañé, L., Flores-Le Roux, J. A., Gómez, N., Chillarón, J. J., Llauradó, G., Gortazar, L., Payà, A., Pedro-Botet, J., & Benaiges, D. (2019) · Diabetes Research and Clinical Practice · doi:10.1016/j.diabres.2019.03.017 · Cited by 39 · see citing works
Early pregnancy hemoglobin A1C and pregnancy outcomes: a population-based study
Chen, L., Pocobelli, G., Yu, O., Shortreed, S. M., Osmundson, S. S., Fuller, S., Wartko, P. D., Mcculloch, D., Warwick, S., Newton, K. M., et al. (2019) · American Journal of Perinatology · doi:10.1055/s-0038-1675619 · Cited by 36 · see citing works
Sweeting, A., Hare, M. J., de Jersey, S. J., Shub, A. L., Zinga, J., Foged, C., Hall, R. M., Wong, T., & Simmons, D. (2025) · Medical Journal of Australia · doi:10.5694/mja2.52696 · Cited by 26 · see citing works
Hughes, R. C. E., Williman, J., & Gullam, J. E. (2016) · PLOS ONE · doi:10.1371/journal.pone.0156926 · Cited by 19 · see citing works
Self-citationBoe, B., Barbour, L. A., Allshouse, A. A., & Heyborne, K. D. (2019) · American Journal of Obstetrics & Gynecology MFM · doi:10.1016/j.ajogmf.2019.02.003 · Cited by 16 · see citing works
Diagnosis of gestational diabetes: Evidence and pitfalls
Wong, T., Immanuel, J., Wong, V. W., Barnes, R., & Simmons, D. (2025) · Best Practice & Research Clinical Endocrinology & Metabolism · doi:10.1016/j.beem.2025.102069 · Cited by 4 · see citing works
- Authors
- Hughes, R. C. E., Moore, M. P., Gullam, J. E., Mohamed, K., & Rowan, J.
- Affiliations
- University of Otago (NZ)
- Christchurch Hospital (NZ)
- Auckland City Hospital (NZ)
- Corresponding author
- Hughes, Ruth C.E.
- Venue
- Diabetes Care
- Publisher
- American Diabetes Association
- Published
- 2014-10-10
- Volume
- 37
- Issue
- 11
- Pages
- 2953-2959
- ISSN
- 0149-5992 (ISSN-L)
- 1935-5548
- OpenAlex
- W2155177707
- Cited by
- 238
- References
- 4
- Citations by year
- 2026: 9 · 2025: 21 · 2024: 32 · 2023: 18 · 2022: 24 · 2021: 26 · 2020: 22 · 2019: 21 · 2018: 24 · 2017: 19 · 2016: 9 · 2015: 13
- FWCI
- 14.51
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Diabetes Care (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Obstetrics and Gynecology › Gestational Diabetes Research and Management
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes Management and Research
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes, Cardiovascular Risks, and Lipoproteins
- Keywords
- gestational diabetes mellitus, HbA1c thresholds, early pregnancy, oral glucose tolerance test, gestational diabetes screening, adverse pregnancy outcomes, major congenital malformations, preeclampsia, shoulder dystocia, perinatal death, diagnostic accuracy, prenatal care, early intervention
- MeSH terms
- Adult, Female, Glucose Tolerance Test, Glycated Hemoglobin, Humans, New Zealand, Pre-Eclampsia, Pregnancy, Pregnancy Outcome, Prospective Studies, Risk, Cohort Studies, Diabetes, Gestational, Young Adult
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