Sweet Expectations: Understanding and Managing Gestational Diabetes

Plus, tips for managing pre-existing diabetes during pregnancy

If you develop gestational diabetes during your pregnancy or are already living with type 1 or type 2 diabetes and become pregnant, you can still experience a healthy pregnancy and delivery.¹ Managing your blood sugar levels effectively during pregnancy benefits both you and your baby.

Read on to find out more about gestational diabetes causes, symptoms, treatments, and helpful advice for managing diabetes and pregnancy.

Gestational diabetes mellitus is a specific type of diabetes that can develop during pregnancy.¹ If you have diabetes before getting pregnant, it’s called pregestational diabetes, or pre-existing diabetes. 

What is gestational diabetes mellitus?

During pregnancy, your body undergoes numerous changes, some of which can impact how it processes glucose (sugar). These changes can lead to glucose intolerance, which in turn results in high blood sugar levels.^1,2 This condition is known as gestational diabetes mellitus (GDM).

GDM is a specific type of diabetes that develops during pregnancy, typically in the second or third trimester. It is different from pregestational diabetes, which refers to having diabetes before becoming pregnant (also called pre-existing diabetes).¹

How Common is Gestational Diabetes Mellitus (GDM)?

The number of people with gestational diabetes is increasing worldwide, affecting around 9 to 25% of pregnancies.² This is due to factors such as increases in maternal age and the prevalence of obesity among women of childbearing age.³ 

Risk factors of gestational diabetes mellitus 

Gestational diabetes can increase the risk of type 2 diabetes later in life for both you and your baby.³ However, if you manage your blood sugar well during pregnancy, you can help decrease the risk.

Gestational diabetes may increase the likelihood of developing it again in the future, and it’s linked to an increased risk of cardiovascular disease, obesity, and high blood pressure.³ While there's a possibility of your baby facing heart issues early on and a slightly increased risk of childhood obesity, healthcare measures can help manage and reduce these risks.

What causes gestational diabetes mellitus?

Gestational diabetes develops during pregnancy as a result of placental hormones and human placental lactogen, making the body more resistant to insulin.³ In a healthy pregnancy, the body adjusts to rising insulin resistance by producing more insulin. However, this process does not always work correctly, and there may not be enough insulin to keep up with the increasing resistance. As a result, blood sugar levels increase slightly, and the extra glucose easily goes through the placenta to provide energy for the baby's growth. This mild insulin resistance also leads to the body producing more of its own glucose and breaking down stored fat, causing blood glucose to rise even more.

There are other factors that contribute to gestational diabetes, such as:^3–5

• Obesity or being overweight
• Excessive weight gain in the first and second trimesters of your pregnancy
• Family history of diabetes
• Polycystic ovary syndrome (PCOS)

You and your healthcare provider can work together to manage your weight and reduce the risk of developing gestational diabetes.

Gestational diabetes symptoms

Signs of gestational diabetes often go unnoticed as they can be similar to early pregnancy symptoms. However, if your blood glucose levels increase, you might notice some mild signs such as:⁶

• Feeling tired or weak
• Feeling thirstier than usual
• Urinating often

To find out if you actually have gestational diabetes, your healthcare provider will first need to rule out pre-existing diabetes (pregestational). Then, more tests will confirm or rule out gestational diabetes. The best time to get checked for gestational diabetes is after 24 weeks of pregnancy.⁷ 

About 70 to 85% of women who are diagnosed with gestational diabetes can control their condition by making changes to their lifestyle without needing medicine.⁸

A proactive approach to managing diabetes during pregnancy, whether it’s pre-existing type 1, type 2, or gestational diabetes, can help to ensure a healthier pregnancy for you and your baby.⁸ 

Here are some helpful tips you can follow to help you manage your diabetes while pregnant.

Go to every check-up

Pregestational and gestational diabetes

Even if you’re feeling great, it’s important to go to every prenatal care check-up. Keeping up your appointments with your healthcare team is an essential part of your pregnancy. This way, you and your baby can be closely monitored to ensure everything is going according to plan. 

Know your new target blood glucose levels

Pregestational diabetes

Your doctor can give you personalized blood sugar levels to aim for while pregnant. However, the recommended target numbers for most pregnant women who have pre-existing diabetes (type 1, type 2) are:⁸

• 70–95 mg/dL (3.9–5.3 mmol/L) before meals and overnight
• 110–140 mg/dL (6.1–7.8 mmol/L) an hour after you eat
• 100–120 mg/dL (5.6–6.7 mmol/L) two hours after you eat

 Gestational diabetes

For gestational diabetes (not treated with insulin), the target range for blood glucose levels are:^3,8

• Below 95 mg/dL (5.3 mmol/L) before meals and overnight
• Below 140 mg/dL (7.8 mmol/L) an hour after you eat
• Below 120 mg/dL (5.6–6.7 mmol/L) two hours after you eat

 For gestational diabetes (treated with insulin), the target range for blood glucose levels are:^3,8

• 70 - 95 mg/dL (3.9-5.3 mmol/L) before meals and overnight
• 110 - 140 mg/dL (6.1 -7.8 mmol/L) an hour after you eat
• 100 - 120 mg/dL (5.6-6.7 mmol/L) two hours after you eat

 You should also consistently monitor your blood glucose levels. Talk to your healthcare provider about what target blood glucose levels are right for you during your pregnancy.

Consider working with a dietitian

Pregestational diabetes

Eating healthy foods is an important part of managing blood glucose during pregnancy.⁸ Consider working with a dietitian—alongside your healthcare provider—who can create a healthy meal plan for your pregnancy. 

 A dietician can also help you learn more about how to control blood glucose levels while pregnant and can also guide you in determining the optimum amount of weight you should gain during your pregnancy.¹⁰

Gestational diabetes

For gestational diabetes, medical nutrition therapy (MNT) is a fundamental part of treatment, and many women can successfully meet their health targets through dietary management alone.¹ Additionally, research shows that including probiotics in your pregnancy diet can positively impact your metabolism, help reduce blood glucose levels, and even help prevent gestational diabetes.¹¹

Exercise regularly

Pregestational diabetes

Another important component of managing pre-existing diabetes during pregnancy is ensuring that you have a regular exercise routine. This will help balance your food intake, manage your weight, and help manage your blood glucose.¹² However, those on insulin should be aware of the potential risks of hypoglycemia (where the level of glucose in your blood drops below the normal or ideal range). Check with your doctor to make sure exercise is safe for you. 

Gestational diabetes

If you have a higher body mass index (BMI), staying physically active can potentially lower your risk of gestational diabetes by half.⁴ Swimming and walking are both excellent ideas, as they are both moderate-intensity exercises that raise your heart rate and make you sweat.¹³

Talk to your doctor about the right workouts, and aim for 20-50 minutes of moderate exercise 2 to 7 times a week.⁸

Quickly deal with low blood sugar

Pregestational diabetes

As you work hard to manage your blood glucose levels during pregnancy, you may still encounter low blood glucose levels. If you take insulin or diabetes medicines, it’s essential to have a source of fast sugar to raise your blood glucose levels and prevent hypoglycemia. Glucose tablets, glucose gel, and hard candy are great options. It’s also a good idea to teach close friends, co-workers, and family members how to help you if your blood sugar is ever low. 

Gestational diabetes

Gestational diabetes mainly causes hyperglycemia (where the level of glucose in your blood is higher than the normal or ideal range) and may be treated by using insulin.¹ However, using too much insulin or not eating enough carbohydrates can lead to hypoglycemia.¹² This is why self-monitoring your glucose levels is especially helpful if you need to take oral hypoglycemics or insulin.¹⁴ 

Check your blood sugar often

Pregestational diabetes

Pregnancy can affect your blood sugar,¹ so what worked to maintain normal blood sugar levels before pregnancy may no longer be effective. Your body’s need for energy can change during pregnancy, so checking your blood sugar regularly is key. Regular checks before and after meals will help you understand how your body responds to different foods.⁸ 

Pregestational and gestational diabetes

For both pregestational and gestational diabetes, it’s important to find out how to adjust your medicines, exercise, and food based on your blood glucose tests.⁸ Talk to your doctor about how often you should check your blood glucose levels.

Take insulin as directed

Pregestational diabetes

You might need less insulin in the first trimester and more insulin in the second trimester. As you get closer to the third trimester, you can expect a decrease in insulin needs.⁸ It's important to follow your healthcare provider's guidance on the correct dosage of insulin based on these changes. 

Gestational diabetes

If you have gestational diabetes, insulin may be prescribed if changes to your diet do not bring your blood glucose levels into the target range.¹ 

Pregestational diabetes and gestational diabetes

Insulin is safe for your baby during pregnancy.¹ Your healthcare team will help you manage your insulin or medications to ensure a healthy pregnancy.

Celebrate every step

Managing diabetes during pregnancy can be challenging, and discovering that you have gestational diabetes can come as a surprise. While you might need to make significant changes to your lifestyle, it's important to celebrate every milestone of your pregnancy and not let diabetes define your story. By working together with your healthcare provider, you can manage your diabetes and have a healthy pregnancy.

Sources:

1. Szmuilowicz ED, Josefson JL, Metzger BE. Gestational Diabetes Mellitus. Endocrinol Metab Clin North Am. 2019;48(3):479-493.
2. Alejandro EU, Mamerto TP, Chung G, et al. Gestational Diabetes Mellitus: A Harbinger of the Vicious Cycle of Diabetes. Int J Mol Sci. 2020;21(14):5003.
3. Sweeting A, Wong J, Murphy HR, Ross GP. A Clinical Update on Gestational Diabetes Mellitus. Endocr Rev. 2022;43(5):763-793.
4. Spaight C, Gross J, Horsch A, Puder JJ. Gestational Diabetes Mellitus. In: Stettler C, Christ E, Diem P, eds. Endocrine Development. Vol 31. S. Karger AG; 2016:163-178.
5. De Souza LR, Berger H, Retnakaran R, et al. First-Trimester Maternal Abdominal Adiposity Predicts Dysglycemia and Gestational Diabetes Mellitus in Midpregnancy. Diabetes Care. 2016;39(1):61-64.
6. American Diabetes Association Professional Practice Committee. 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes—2024. Diabetes Care. 2023;47(Supplement_1):S20-S42.
7. Stanford Medicine Children’s Health. Diabetes During Pregnancy. Accessed October 13, 2023.
8. American Diabetes Association Professional Practice Committee. 15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2025. Diabetes Care. 2025;48(1 Suppl 1):S306-S320.
9. Umana OD, Siccardi MA. Prenatal Nonstress Test. In: StatPearls. StatPearls Publishing; 2023. Accessed January 4, 2024.
10. Evert AB, Dennison M, Gardner CD, et al. Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report. Diabetes Care. 2019;42(5):731-754.
11. Homayouni A, Bagheri N, Mohammad-Alizadeh-Charandabi S, et al. Prevention of Gestational Diabetes Mellitus (GDM) and Probiotics: Mechanism of Action: A Review. Curr Diabetes Rev. 2020;16(6):538-545.
12. Low blood glucose in gestational diabetes - hypoglycaemia [Factsheet] [Internet]. RSS Diabetes Service, Government of South Australia. 2021 Sep [cited 2025 Jul 9]. Available from: https://www.chsa-diabetes.org.au/
13. Peters TM, Brazeau AS. Exercise in Pregnant Women with Diabetes. Curr Diab Rep. 2019;19(9):80.
14. Farrar D. Hyperglycemia in pregnancy: prevalence, impact, and management challenges. Int J Womens Health. 2016;Volume 8:519-527.