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 to minimize risks of complications and long-term effects on both mother and child, as supported 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 physical activity (30 minutes of moderate exercise most days)
- Blood glucose monitoring 4-7 times daily Target blood glucose levels are typically less than 95 mg/dL fasting and less than 140 mg/dL one hour after meals.
Medication Therapy
If lifestyle changes don't adequately control blood glucose levels, 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. Some providers may prescribe oral agents like metformin or glyburide, though insulin remains the preferred choice.
Importance of Management
Most women with GDM return to normal blood glucose levels after delivery, but they have a 35-60% chance of developing type 2 diabetes within 10 years, making postpartum screening at 6-12 weeks and regular follow-up essential. GDM requires careful management because uncontrolled blood glucose can lead to complications including macrosomia (large baby), birth injuries, neonatal hypoglycemia, and increased risk of cesarean delivery. Telehealth visits for pregnant people with GDM have been shown to improve outcomes compared with standard in-person care 1.
Key Considerations
- Depending on the population, studies suggest that 70–85% of people diagnosed with GDM under Carpenter-Coustan criteria can manage GDM with lifestyle modification alone 1.
- The risk of GDM may be reduced by diet, exercise, and lifestyle counseling, particularly when interventions are started during the first or early in the second trimester 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 that are first recognized during pregnancy 2.
- The prevalence of GDM is increasing in the United States, and it is associated with various complications, including operative delivery, hypertensive disorders, shoulder dystocia, fetal macrosomia, and neonatal hypoglycemia 2, 3.
- GDM is a significant concern in obstetric care, as it increases the risk of adverse outcomes for both the mother and the fetus, including preterm delivery, low birth weight, and respiratory distress syndrome 4.
Management of GDM
- The management of GDM typically involves lifestyle modifications, such as dietary changes and physical activity, to control blood sugar levels 2.
- For patients who are unable to maintain euglycemia with lifestyle modifications alone, insulin is the recommended first-line medication 2.
- Fetal surveillance is suggested starting at 32 weeks of gestation for patients with poor glucose control or who require medications 2.
- The recommended delivery range for patients controlling their glucose levels with lifestyle modifications alone is 39/0 to 40/6 weeks of gestation, and the ideal range for those controlling glucose levels with medications is 39/0 to 39/6 weeks of gestation 2.
Complications and Risks Associated with GDM
- GDM is associated with an increased risk of fetal macrosomia, which can lead to complications such as shoulder dystocia, clavicle fractures, and brachial plexus injury 5.
- 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.
- GDM is also associated with an increased risk of preeclampsia, which can further increase perinatal adverse events and have a greater impact on future maternal and offspring health 6.
- Women with GDM have an increased risk of developing overt diabetes after delivery, but continued lifestyle modifications, breastfeeding, and use of metformin can reduce this risk 2.