What is gestational diabetes mellitus (GDM) and how is it managed?

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From the Guidelines

Gestational diabetes mellitus (GDM) is a type of diabetes that develops during pregnancy in women who didn't have diabetes before becoming pregnant, and its management should prioritize lifestyle modifications and insulin therapy as the first-line treatment, as recommended by the most recent guidelines 1.

Definition and Significance

GDM occurs when the body cannot produce enough insulin to meet the extra needs during pregnancy, resulting in high blood glucose levels. It typically develops in the second or third trimester and affects approximately 2-10% of pregnancies. GDM is characterized by an increased risk of large-for-gestational-age birth weight and neonatal and pregnancy complications, as well as an increased risk of long-term maternal type 2 diabetes and abnormal glucose metabolism in offspring in childhood 1.

Management

Management of GDM begins with lifestyle modifications, including:

  • A balanced diet low in simple carbohydrates
  • Regular moderate exercise (30 minutes daily)
  • Blood glucose monitoring 4-7 times daily Target blood glucose levels are typically below 95 mg/dL fasting and below 140 mg/dL one hour after meals. If lifestyle changes are insufficient, medication may be necessary. Insulin is the preferred medication for treating hyperglycemia in GDM, as it does not cross the placenta to a measurable extent 1.

Key Recommendations

  • Lifestyle behavior change is an essential component of management of GDM and may suffice as treatment for many individuals 1.
  • Insulin should be added if needed to achieve glycemic targets 1.
  • Metformin and glyburide should not be used as first-line agents, as both lack long-term safety data 1.
  • Telehealth visits for pregnant people with GDM improve outcomes compared with standard in-person care 1.

Importance of Regular Prenatal Visits

Regular prenatal visits are essential to monitor both maternal and fetal health. GDM usually resolves after delivery, but women who have had GDM have a 50% increased risk of developing type 2 diabetes later in life, making postpartum glucose testing at 6-12 weeks and regular screening thereafter important 1.

From the Research

Definition of Gestational Diabetes Mellitus (GDM)

  • Gestational diabetes mellitus (GDM) is defined as a glucose intolerance resulting in hyperglycaemia of variable severity with onset during pregnancy 2.
  • It is a state of hyperglycemia that is first recognized during pregnancy 3.
  • GDM is characterized by any degree of glucose intolerance with onset or first recognition during pregnancy 4.

Significance and Relevance to Obstetric Care

  • GDM is the most common medical complication of pregnancy, affecting approximately 15% of pregnancies worldwide 3.
  • It increases the risk of complications, including operative delivery, hypertensive disorders, shoulder dystocia, fetal macrosomia, large-for-gestational-age infants, neonatal hypoglycemia, and neonatal respiratory distress 5.
  • GDM also increases the risk of long-term complications, including obesity, impaired glucose metabolism, and cardiovascular disease, in both the mother and infant 6.
  • The diagnosis and treatment of GDM are crucial to reduce the risk of adverse pregnancy outcomes and long-term complications 5, 6.

Management of GDM

  • The primary treatments for GDM are diet and increased exercise 3.
  • Insulin, glibenclamide, and metformin can be used to intensify the treatment 3.
  • Lifestyle modifications, including prepregnancy weight loss and lifestyle modifications during pregnancy, may prevent GDM in patients who are overweight or obese 5.
  • Treatment of GDM should start with lifestyle modifications, and insulin is the recommended first-line medication for patients who are unable to maintain euglycemia with lifestyle modifications alone 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Gestational Diabetes Mellitus-Recent Literature Review.

Journal of clinical medicine, 2022

Research

Gestational diabetes mellitus.

Nature reviews. Disease primers, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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