Gestational diabetes mellitus (GDM) is a form of diabetes that occurs during a woman’s pregnancy when blood sugar levels are too high. Half of the women with gestational diabetes go on to develop type 2 diabetes, according to the Centers for Disease Control and Prevention (CDC).
Blood sugar, or blood glucose, must be closely monitored throughout pregnancy to ensure no serious complications occur. This article will examine the blood sugar level charts for gestational diabetes and how blood glucose levels are measured.
What Is Gestational Diabetes?
Gestational diabetes is a type of metabolic condition marked by high blood sugar levels among pregnant women. It is the most common complication that occurs during pregnancy.
Like other diabetic conditions, gestational diabetes occurs due to impaired insulin sensitivity — also known as insulin resistance. Type 2 diabetes is the most common type of insulin-resistant diabetes.
What Is Insulin?
Insulin is a naturally occurring hormone that is produced by the pancreas. It is a key player when it comes to metabolism. Metabolism refers to the chemical process that takes place to help break down and convert food to energy.
When you eat or drink, your digestive system helps break down macronutrients called carbohydrates into an energy source known as glucose — a type of sugar. Ketones are the chemicals that break down fats for fuel.
When this sugar, or glucose, is released into the bloodstream, it causes blood sugar levels to rise. As levels rise, the pancreas is triggered to release insulin to help control the rise in blood sugar. Insulin helps push glucose into the cells, to be used as fuel.
Under normal conditions, this process is a constant feedback loop. When blood sugar levels rise, insulin helps maintain homeostasis by keeping levels within normal range. The more glucose in the bloodstream, the more insulin is required.
What Are the Types of Diabetes?
Diabetes occurs when the metabolic system is not functioning properly. There are three main subtypes of diabetes: Type 1 diabetes, type 2 diabetes, and gestational diabetes.
Type 1 Diabetes (Insulin-Dependent)
This type of diabetes is also known as juvenile diabetes because it is an autoimmune disorder that typically occurs in childhood. That said, it is still possible to get diagnosed with type 1 diabetes as an adult.
In short, the immune system targets and attacks healthy beta cells that produce insulin.
With type 1 diabetes, the body cannot make enough insulin to manage blood sugar effectively. The result is high blood sugar levels. In most cases, type 1 diabetes requires daily insulin injections.
Type 2 Diabetes
Unlike type 1 diabetes, type 2 is considered a progressive disease that happens over time. It can affect adults and children. While numerous risk factors are associated with type 2 diabetes, obesity is one of the most common factors.
In type 2 diabetes, the body is usually unable to both use insulin effectively (known as insulin resistance), while also not being able to produce enough insulin to control high blood sugar levels.
Gestational Diabetes
Gestational diabetes is a form of type 2 diabetes that occurs during pregnancy. Some insulin resistance is normal during pregnancy due to hormonal changes, placenta hormone production, and weight gain.
But, sustained levels of high blood sugar (hyperglycemia) throughout pregnancy can warrant a gestational diabetes diagnosis.
What Are the Symptoms of Gestational Diabetes?
It is normal for gestational diabetes to have no noticeable symptoms. When closely monitored, many women go on to have a healthy pregnancy and deliver a healthy baby.
However, mild gestational diabetes symptoms can include:
- Weight gain
- Frequent urination
- Tiredness or general fatigue
- Excessive thirst and hunger
Gestational diabetes can also make other medical conditions worse. These include high blood pressure, known as preeclampsia, during the later weeks of pregnancy.
There is also an increased risk of delivering a larger-than-average baby, known as infant macrosomia. Higher birth weight can lead to an emergency cesarean delivery (C-section).
How Do You Test for Gestational Diabetes?
Prenatal care screenings for gestational diabetes occur throughout pregnancy. Oral glucose tolerance tests are often done in later trimesters. Also, glucose monitoring is done throughout follow-up visits with health care providers if gestational diabetes is suspected.
Pregnant women drink a sugary solution on a fasted stomach for this test. Healthcare professionals draw a blood sample to check fasting glucose levels.
Other types of blood glucose testing include fasting blood sugar tests, glucose tolerance tests, and A1C tests. The fasting blood sugar and glucose tolerance tests use milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L).
The A1C test, or HbA1C test, measures average blood sugar levels over a few months, typically two to three months. It is one of the most definitive blood glucose tests. The A1C is measured as a percentage.
Target Levels per Glucose Test
| Normal | Prediabetes | Diabetes | |
| A1C Test | 5.7% or less | 5.7 – 6.4% | 6.5% or more |
| Glucose Tolerance Test | 140 mg/dL or below | 140 – 199 mg/dL | 200 mg/dL or above |
| Fasting Blood Sugar Test | 99 mg/dL or less | 100 – 125 mg/dL | 126 mg/dL or more |
Blood Sugar Level Charts for Gestational Diabetes
Blood sugar level charts are resources that help people manage their blood sugar by providing healthy glucose ranges. The American Diabetes Association (ADA) puts out the target range recommendations.
That said, these charts should only be used for reference, since someone’s “normal” blood sugar range can vary depending on their overall health, whether or not they have diabetes, their concurrent medical conditions, and much more. People with diabetes should always consult their physicians for guidance on what their target blood sugar range should be.
Normal Blood Sugar Chart per ADA
Fasting
| Normal range for a person without diabetes | 70-99 mg/dL |
| For someone with diabetes per ADA | 80-130 mg/dL |
2 hours after a meal
| Normal range for a person without diabetes | Less than 140 mg/dL |
| For someone with diabetes per ADA | Less than 180 mg/dL |
A1C, or HbA1C
| Normal range for a person without diabetes | Less than 5.7% |
| For someone with diabetes per ADA | 7% or less |
Target Blood Sugar Levels During Pregnancy
| Blood sugar level before meals | 95 mg/dL or less |
| Blood sugar level 1 hour after eating | 140 mg/dL or less |
| Blood sugar level 2 hours after eating | 120 mg/dL or less |
These are based on recommendations by the American College of Obstetricians and Gynecologists (ACOG).
Target Blood Sugar Levels for Pre-existing Diabetes & Gestational Diabetes
| Pre-existing Diabetes | Gestational Diabetes |
| Fasting / Before a meal: 60 to 99 mg/dL | Fasting / Before a meal: 95 mg/dL or less |
| 1-2 hours after a meal: 140 mg/dL or less | 1 hour after a meal: 120 mg/dL or less |
How Do I Track Blood Sugar Levels?
In most cases, if gestational diabetes is suspected, a glucose meter will be part of your diabetes care plan. These can measure your blood sugar levels. Glucose meters measure blood sugar from small drops of blood drawn from finger pricks.
A diabetes educator or member of your OBGYN’s health care team will review the procedures of testing blood sugar during your prenatal visits. This includes how to track health information like blood sugar levels and weight.
Keeping logs of your daily glucose levels can show your health care provider how your blood sugar levels change through your day and through various activities like exercising or working at your desk all day. .
Risk Factors for Gestational Diabetes
Maternal age, obesity (BMI greater than 25), a sedentary lifestyle, and lack of physical activity are serious risk factors for gestational diabetes.
Other risk factors include:
- Family history of diabetes
- Diagnosis of prediabetes
- Diagnosis of gestational diabetes in a previous pregnancy
- Being Latino American, Asian American, Pacific Islander, or African American.
How Do I Prevent and Manage Gestational Diabetes?
The good news is, in many cases, gestational diabetes is completely preventable. It starts by establishing healthy lifestyle habits and routines before pregnancy.
Since obesity is a serious risk factor, maintaining a healthy weight before and during pregnancy is very important. This is where dietary changes and exercise come into play.
A healthy meal plan and daily aerobic exercise can do wonders. You can do this with the help of a dietitian. Exercise doesn’t have to be strenuous; it can include low-impact exercises like walking, swimming, yoga, hiking, and more. The goal should be 30 minutes three to four times a week.
The Bottom Line
Gestational diabetes is a metabolic condition that occurs during pregnancy. This condition can cause serious pregnancy complications for the mother and the baby if left untreated.
Routine blood sugar level checks during prenatal care visits and at home with glucose monitoring are one way to monitor this disorder.
Thankfully, gestational diabetes can be preventable, but it requires some healthy lifestyle changes.
References, Studies and Sources:
Gestational Diabetes Mellitus | ACOG
6. Glycemic Targets: Standards of Medical Care in Diabetes—2021 | ADA
Maternal Obesity and Risk of Gestational Diabetes Mellitus | Diabetes Journal
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Diabetic.org is devoted to producing expert and accurate articles and information for our readers by hiring experts, journalists, medical professionals, and our growing Diabetic.org community. We encourage you to read more about our content, editing, and fact checking methods here. This was fact checked by Camille Freking and medically reviewed by Dr. Angel Rivera.
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