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 did not have diabetes before becoming pregnant, and its management begins with lifestyle modifications, with insulin as the first-line medication therapy if needed, 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 sugar 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 physical activity (30 minutes of moderate exercise most days)
  • Blood glucose monitoring 4-7 times daily (fasting and 1-2 hours after meals) Target blood glucose levels are typically less than 95 mg/dL fasting and less than 140 mg/dL one hour after meals. If lifestyle changes are insufficient, medication may be necessary, with insulin as the first-line medication therapy during pregnancy, as it does not cross the placenta to a measurable extent 1.

Medication Therapy

Insulin regimens may include long-acting insulin (like insulin detemir or insulin glargine) once or twice daily and rapid-acting insulin (like insulin aspart or insulin lispro) before meals. Oral agents such as metformin or glyburide may be used in some cases, but they should not be used as first-line agents due to the lack of long-term safety data 1.

Importance of 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 screening and long-term follow-up important 1.

Recent Guidelines

The most recent guidelines recommend that lifestyle behavior change is an essential component of management of GDM and may suffice as treatment for many individuals, with insulin added if needed to achieve glycemic targets 1. Telehealth visits for pregnant people with GDM have also been shown to improve outcomes compared with standard in-person care 1.

Key Points

  • GDM is a type of diabetes that develops during pregnancy
  • Management begins with lifestyle modifications
  • Insulin is the first-line medication therapy if needed
  • Regular prenatal visits are essential to monitor maternal and fetal health
  • Women who have had GDM have a 50% increased risk of developing type 2 diabetes later in life, making postpartum screening and long-term follow-up important 1.

From the Research

Definition and Significance of Gestational Diabetes Mellitus (GDM)

  • Gestational diabetes mellitus (GDM) is a common condition of pregnancy characterized by high blood sugar levels, first recognized during pregnancy 2.
  • GDM increases the risks of complications, including operative delivery, hypertensive disorders, shoulder dystocia, fetal macrosomia, large-for-gestational-age infants, neonatal hypoglycemia, and neonatal respiratory distress 2.
  • The prevalence of GDM is rising and correlates with the increase in maternal obesity over recent decades 3.

Management and Treatment of GDM

  • Treatment of GDM has been shown to reduce the risk of complications and should start with lifestyle modifications, such as diet and exercise 2.
  • For patients who are unable to maintain euglycemia with lifestyle modifications alone, insulin is the recommended first-line medication 2.
  • First-trimester screening can identify preexisting diabetes and early-onset GDM for prompt implementation of glucose control measures 2, 4.
  • Fetal surveillance is suggested starting at 32 weeks of gestation for patients with poor glucose control or who require medications 2.

Complications and Risks Associated with GDM

  • Fetal macrosomia, defined as a birth weight ≥ 4,000 g, is a common adverse infant outcome of GDM if unrecognized and untreated in time 5.
  • GDM complicated by preeclampsia further increases perinatal adverse events with greater impact on the future maternal and offspring health 6.
  • Infants of women with GDM are at an increased risk of becoming overweight or obese at a young age and are more likely to develop type II diabetes later in life 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Gestational Diabetes Mellitus: Mechanisms, Treatment, and Complications.

Trends in endocrinology and metabolism: TEM, 2018

Research

Early Gestational Diabetes Mellitus: An Update.

The Journal of the Association of Physicians of India, 2023

Research

Gestational diabetes mellitus and macrosomia: a literature review.

Annals of nutrition & metabolism, 2015

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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