From the Guidelines
Pregnant patients with gestational diabetes mellitus (GDM) class A1 should be started on medical treatment, specifically insulin, if lifestyle behavior changes, such as diet and exercise, fail to achieve glycemic targets after 1-2 weeks of intervention. According to the most recent guidelines, lifestyle behavior change is an essential component of GDM management and may suffice as treatment for many individuals, but insulin should be added if needed to achieve glycemic targets 1. The American Diabetes Association recommends that insulin is the preferred medication for treating hyperglycemia in GDM, as other oral and noninsulin injectable glucose-lowering medications lack long-term safety data 1.
Some key points to consider when initiating medical treatment for GDM class A1 include:
- Insulin is the preferred first-line medication due to its safety profile and efficacy 1
- Metformin and glyburide should not be used as first-line agents, as both cross the placenta to the fetus 1
- The goal of treatment is to reduce the risk of macrosomia, neonatal hypoglycemia, and other complications associated with maternal hyperglycemia
- Blood glucose should be monitored regularly, and medication doses should be adjusted as needed to achieve target glucose levels
It's essential to note that 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. However, if these interventions fail to achieve glycemic targets, medical treatment with insulin should be initiated to minimize the risks associated with maternal hyperglycemia.
From the Research
Gestational Diabetes Mellitus (GDM) Class A1 Treatment
- The decision to start medical treatment for a pregnant patient with GDM class A1 depends on several factors, including blood glucose levels and response to diet and lifestyle modifications 2.
- According to a study published in 2019, pharmacologic therapy should be considered in women with gestational diabetes when, despite an adequate diet and exercise, 1 or 2 blood glucose values are over the target values of 90mg/dL fasting or 120mg/dL 2-hour postprandial over 1 or 2 weeks 2.
- The study found that the majority of randomized controlled trials (87%) used very tight criteria of either 1 or 2 values over the target values in the 1 or 2-week period for starting pharmacologic treatment for patients with GDM 2.
- Another study published in 2021 found that lifestyle modifications were the most common mode of management for GDM, but 38.5% of women with GDM had poor glycemic control, highlighting the need for closer monitoring and potential medical treatment 3.
- A 2024 study compared the effects of insulin and metformin on GDM and found that both treatments were effective in achieving glycemic control, with no significant difference in time-in-range (TIR) metrics between the two groups 4.
- A 2023 study found that insulin aspart combined with metformin was effective in reducing blood-glucose-related indexes, inflammatory markers, and the risk of adverse pregnancy outcomes and complications in women with GDM 5.
- A 2013 study found that fasting blood glucose at oral glucose tolerance test (OGTT) was a significant predictor of response to metformin monotherapy in women with GDM, with a fasting glucose ≤5.2 mmol/L predicting a 93% response rate to metformin 6.
Key Considerations
- Blood glucose targets: 90mg/dL fasting or 120mg/dL 2-hour postprandial 2
- Criteria for starting pharmacologic treatment: 1 or 2 values over the target values in the 1 or 2-week period 2
- Importance of close monitoring and potential medical treatment for women with GDM who do not respond to lifestyle modifications 3
- Effectiveness of insulin and metformin in achieving glycemic control in women with GDM 4, 5
- Predictors of response to metformin monotherapy, including fasting blood glucose at OGTT 6