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Gestational diabetes mellitus

Last reviewed: 11 Apr 2025
Last updated: 06 Dec 2024

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • abnormal oral glucose tolerance test
Full details

Other diagnostic factors

  • polyuria
  • polydipsia
  • fetal macrosomia
Full details

Risk factors

  • advanced maternal age (>40 years)
  • elevated BMI
  • polycystic ovarian syndrome (PCOS)
  • ancestry
  • family history of type 2 diabetes mellitus
  • previous gestational diabetes
  • previous macrosomic baby
Full details

Diagnostic tests

1st tests to order

  • one-step test option: 75-g oral glucose tolerance test (OGTT)
  • two-step test option: 1-hour 50-g glucose load test (GLT), followed by 3-hour 100-g OGTT
Full details

Tests to consider

  • fasting blood (plasma) glucose
  • random blood (plasma) glucose
Full details

Treatment algorithm

ACUTE

pregnant

labor

Contributors

Authors

Ellen W. Seely, MD

Professor of Medicine

Harvard Medical School

Director of Clinical Research

Endocrinology, Diabetes and Hypertension Division

Brigham & Women's Hospital

Boston

MA

Disclosures

EWS declares that she has no competing interests.

Chloe Zera, MD, MPH

Associate Professor

Harvard Medical School

Director, Network Obstetrics Population Health

Division of Maternal Fetal Medicine

Department of Obstetrics and Gynecology

Beth Israel Deaconess Medical Center

Boston

MA

Disclosures

CZ declares that she receives author royalties from UpToDate.

Acknowledgements

Dr Ellen W. Seely and Dr Chloe Zera would like to gratefully acknowledge Dr Jeremy Soule and Dr Leonard E. Egede, previous contributors to this topic.

Disclosures

JS has undertaken research support and speakers' bureau activity for Novartis, Bristol Myers Squibb, Astra Zeneca, and Sanofi-Aventis. LEE is an author of a number of references cited in this topic.

Peer reviewers

Rajesh K. Garg, MD

Professor of Medicine

Director of Clinical Diabetes

University of Miami

Miami

FL

Disclosures

RKG declares that he has no competing interests.

Wail Malaty, MD

Clinical Professor

Department of Family Medicine

University of North Carolina

Chapel Hill

Assistant Program Director

MAHEC Rural Family Medicine Residency

Hendersonville

NC

Disclosures

WM declares that he has no competing interests.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

American Diabetes Association. Introduction and methodology: standards of care in diabetes - 2024. Diabetes Care 2024;47(Suppl. 1):S1-S4.Full text

Plows JF, Stanley JL, Baker PN, et al. The pathophysiology of gestational diabetes mellitus. Int J Mol Sci. 2018 Oct 26;19(11):E3342.Full text  Abstract

Blonde L, Umpierrez GE, Reddy SS, et al. American Association of Clinical Endocrinology clinical practice guideline: developing a diabetes mellitus comprehensive care plan-2022 update. Endocr Pract. 2022 Oct;28(10):923-1049.Full text  Abstract

Metzger BE, Gabbe SG, Persson B, et al; International Association of Diabetes and Pregnancy Study Groups Consensus Panel. International association of diabetes and pregnancy study groups recommendations on the diagnosis and classification of hyperglycemia in pregnancy. Diabetes Care. 2010 Mar;33(3):676-82.Full text  Abstract

American College of Obstetricians and Gynecologists. ACOG practice bulletin no.190: gestational diabetes mellitus. Feb 2018 [internet publication].Full text

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.
  • Differentials

    • Type 1 diabetes
    • Type 2 diabetes
    More Differentials
  • Guidelines

    • Standards of care in diabetes
    • Practice bulletin no. 229: antepartum fetal surveillance
    More Guidelines
  • Patient information

    Diabetes that develops in pregnancy (gestational diabetes)

    Diabetes type 2: what treatments work?

    More Patient information
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