Gestational Diabetes

Last Update: 18 Nov 2024

Condition

Table of content

1. What is it? 2. Why Treating? 3. Breastfeeding 4. Non-Medical Options 5. Medications 6. Key Takeaways 7. Limits of Research

Welcome to our Fact Sheet on gestational diabetes, a form of diabetes first diagnosed during pregnancy. The information is based on current research and may be updated as new scientific knowledge emerges. It’s important to remember that the content shared here does not replace personalized advice from healthcare professionals.

1. What Is Gestational Diabetes and How to Recognize the Symptoms?

Diabetes happens when there’s a problem with a lock-and-key mechanism in the body where insulin, the key, unlocks cells to let sugar (glucose) in for energy. A disruption in this lock-and-key mechanism can lead to abnormally high sugar levels (hyperglycemia) and further associated consequences. Multiple factors can disrupt the balance of the insulin lock-and-key mechanism leading to one of the 3 types of diabetes: Type 1, Type 2, and gestational.

In gestational diabetes, challenges with sugar regulation are mainly caused by hormonal changes initiated by the placenta. Indeed, the natural hormonal changes can make it harder for the insulin key to work properly, trapping the sugar in the bloodstream (hyperglycemia) in both the mother and baby. The mother’s pancreas must produce 2 to 3 times more insulin during pregnancy to compensate. Although increased insulin production is normal to support the baby’s growth, about 1 in 10 pregnant women may struggle more with their lock-and-key mechanism and develop gestational diabetes.

Detection in the second half of pregnancy, or earlier if needed, is important as gestational diabetes often has no symptoms, underscoring the importance of regular screening. However, some indicators such as heightened thirst, frequent urination, fatigue, nausea, and the presence of sugar in urine samples collected during prenatal check-ups should be monitored.

First a screening test is used which then needs a diagnostic test if the screening shows possible risk. The screening test for gestational diabetes, known as a glucose tolerance test, is usually performed between the 24^th and 28^th weeks of pregnancy when the body’s insulin needs are heightened. For the test, you will need to visit a healthcare facility for a morning appointment. Whether you need to fast beforehand depends on the specific test given. The glucose tolerance test can take up to 2 hours and involves drinking a sugary solution followed by blood measurements to check your glucose levels (see Table 1). Depending on the results, a follow-up test may be required to confirm the diagnosis.

Should you be screened for gestational diabetes?

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Table 1. Timeline outlining the steps involved in the glucose tolerance test.

1- Sugar intake and wait	2- Blood Sugar Measurement
Drink a sweet beverage representing a daily sugar intake (usually 50 g). It’s the equivalent of approximately 15 teaspoons of sugar.	Blood test done 1 to 2 hour later to check blood sugar levels.

1- Sugar intake and wait

2- Blood Sugar Measurement

Drink a sweet beverage representing a daily sugar intake (usually 50 g).

It’s the equivalent of approximately 15 teaspoons of sugar.

Blood test done 1 to 2 hour later to check blood sugar levels.

Did you know that gestational diabetes can affect anyone, regardless of weight or lifestyle?

Indeed, as the main risk factor is the hormonal changes caused by the placenta, even a mom within an ideal weight range who leads a healthy lifestyle can develop gestational diabetes. However, certain factors (see table 2) may increase your personal risk.

Table 2. Risk factors for developing gestational diabetes during pregnancy.

Risk Factor	Description
Mother age	Being pregnant at 35 years old or above.
Family history of type 2 diabetes. Prediabetes sugar levels or a history of gestational diabetes.	Having a family history of type 2 diabetes. Having higher sugar levels than average before pregnancy, but not to the extent of diabetes. Previously having gestational diabetes in a pregnancy or giving birth to a baby weighing over 4 kg.
Weight	Having a body mass index (BMI) greater than or equal to 30 kg/m².
At-risk ethnic groups	Recent studies show that Indigenous, African, Arab, Asian, Hispanic, or South Asian ethnic groups may have a higher risk due to specific metabolism or social factors affecting health. For example, Canadian Indigenous communities face an increased risk, up to nearly 1 in 5 pregnancies (18%).
Certain medical conditions or medications	Having polycystic ovary syndrome, acanthosis nigricans (darkened patches of skin), or using corticosteroid medication.

If you have any of these risk factors, your healthcare provider may recommend undergoing the glucose tolerance test right after your first pregnancy appointment to determine if, even in the first trimester, there’s already a higher level of sugar than expected (glucose intolerance).

2. Why Is It Important to Treat Gestational Diabetes During Pregnancy?

Miscarriages, congenital malformations tooltip, premature birth, and other complications can happen in any pregnancy for many different reasons. This is the background risk. Here we compare this background risk with the risks associated with the untreated condition.

Gestational diabetes usually doesn’t increase the chance of congenital malformations in your baby compared to the background risk, which is around 3 out of 100 pregnancies. However, gestational diabetes has been associated with increased risks of pregnancy complications for the mother, the unborn child, and the family ( Table 3).

Some studies have shown that some ethnic groups are more at risk of developing gestational diabetes. Also, other groups, including Asian/Pacific Islanders, Caucasians, Hispanics, and Black individuals, may have a higher risk of certain pregnancy-related complications associated with gestational diabetes. It’s important to understand that these differences can also be influenced by factors like access to healthcare and lifestyle habits.

If you have concerns, discussing them with your healthcare provider can help you receive the best possible care during your pregnancy. While gestational diabetes can elevate certain risks, early screening and proper management can help minimize these risks, making them similar to those found in pregnancies without health complications.

Table 3. Risks and challenges of untreated gestational diabetes.

For who?	What?	What does research say?
For the pregnant person	Preeclampsia and hypertension	Higher risk of developing high blood pressure and organ damage, particularly the liver and kidneys in about 1 out of 8 cases (up to 1 in 6 cases in Black communities tooltip).
	Polyhydramnios	Excess amniotic fluid leading to complications like preterm labor and placental abruption tooltip).
	Delivery Complications	Increase risk of needing a caesarean section due to the larger baby’s size.
	Future Diabetes	Higher risk of developing type 2 diabetes later in life. About 1 in 2 people who have gestational diabetes will develop type 2 diabetes later in life.
For the unborn child	Larger baby or macrosomia	Increased risk of high birth weight (more than 4.5 kg). This seems a bit more frequent in Black (1 in 4 pregnancies) than in Caucasian (1 in 6 pregnancies) tooltip). The excess sugar is transformed into fat in the baby leading to higher weight and potential delivery complications like shoulder dystocia tooltip).
For the unborn child	Premature Birth	Increased risk of early delivery (before 37 weeks), which can result in respiratory issues and other health problems.
For future child/ adult	Neonatal Hypoglycemia	Low blood sugar levels at birth due to the baby’s pancreas producing extra insulin.
	Jaundice	Higher risk of developing jaundice, characterized by yellowing of skin and eyes at birth.
	Long-term health Issues	Higher risk of obesity and type 2 diabetes in later life.
For the family	Family adjustments	Adapting to a new lifestyle may be challenging, but family support can facilitate the process.

These are group approximations; other factors such as your genetics, other medical conditions, and your lifestyle can vary your own risk.

Once the placenta is delivered, most women (9 out of 10) will no longer have gestational diabetes. Extra testing may be done postpartum to ensure that blood sugar levels have returned to normal levels and catch any potential issues early. If high blood sugar continues after pregnancy, you might be diagnosed with type 2 diabetes.

3. Will I Be Able to Breastfeed?

If you have gestational diabetes, breastfeeding is highly recommended, when possible and desired. As gestational diabetes doesn’t continue after birth, there are no restrictions on breastfeeding. It’s a win-win for both you and your baby. Here’s why:

Table 4. Benefits of breastfeeding after having gestational diabetes.

Benefits for the person breastfeedind	Benefits for baby
Breastfeeding lowers your risk of developing Type 2 diabetes later on and helps you lose pregnancy weight.	Breastfeeding right after birth and for at least 4 months can prevent low blood sugar in your newborn and reduce their risk of childhood obesity and diabetes.

Make sure to talk to your healthcare provider or a lactation consultant about any breastfeeding questions you have.

4. What Can I Do to Manage my Gestational Diabetes Before Medications?

A diagnosis of gestational diabetes can be stressful, but there are effective ways to control sugar level. In fact, in most cases, a few lifestyle changes are sufficient:

Healthy Diet: Eat a balanced diet with controlled carbohydrate intake. Spread your meals throughout the day to keep your blood sugar stable. Focus on whole grains, lean proteins, and lots of vegetables.
Regular Exercise: Engage in moderate activities like walking, swimming, or prenatal yoga to help regulate blood sugar levels.
Monitor Blood Sugar: Regularly check your blood sugar levels to ensure they stay within the target range. Here are the general targets:

Since every pregnancy is different, work with your healthcare team to determine your specific glucose goals and manage your individual risk factors.

Tips for Success: Changing habits can be tough, but involving your partner, friends, and support network can make it easier.

Watch our short video the learn more about gestational diabetes!

Learn more

5. Medications Prescribed for Treating Gestational Diabetes

Sometimes, diet and physical exercise are not enough to manage blood sugar levels. In these cases, your doctor may prescribe medications to help maintain your blood sugar within the desired range.

In Canada, the first choice medical treatment prescribed for gestational diabetes is insulin injections. Research indicates that neither the needles nor the insulin itself reach the baby, making this a safe option that doesn’t affect the baby’s development. In fact, its main action prevents hyperglycemia for the mother, limiting potential complications. For details on the risks and benefits of insulin injections.

In rare cases, where insulin cannot be used or is insufficient, other medications taken orally such as metformin or glyburide may be prescribed. However, these are not typically the first choice in Canada due to limited safety data during pregnancy compared to insulin.

Table 5. Medications Prescribed for Gestational Diabetes

Medication Names	Brand Name
Insulin, Insulin Aspart	Humulin^® R, Humulin^® N, Levemir^® NovoRapid^® and Trurapi^®
Metformin	Glucophage^®
Glyburide	Diabeta^®

Medication Names

Brand Name

Insulin,

Insulin Aspart

Humulin^® R, Humulin^® N, Levemir^®

NovoRapid^® and Trurapi^®

Metformin

Glucophage^®

Glyburide

Diabeta^®

How Do I Know Which One to Take?

Each medication has its benefits and disadvantages, and your healthcare team (pharmacist, nurse, doctor, midwife) is best equipped to guide you in making an informed decision adapted to your specific needs.

Your healthcare team will be the key reference to guide you in choosing the best insulin for you, adjusting the dose, and teaching you safe injection techniques. They will also assist you with adjusting oral antidiabetic medications if needed.

You can see our Fact Sheet about Metformin (Glucophage®) here.

Learn more

Key Takeaways

Gestational diabetes is a temporary condition caused by hormonal changes during pregnancy among other individual risk factors.
Screening for gestational diabetes is routine during the 2nd trimester because symptoms are often silent.
Early diagnosis and management are crucial to prevent complications for both mother and baby.
Most women can manage blood sugar levels through diet and exercise.
Medications like insulin may be needed.
With proper care, most women with gestational diabetes have healthy pregnancies and deliver healthy babies.

7. Research Is Great, But It Is Not Perfect

Making informed health decisions also involves considering the current state of scientific knowledge. Here are some considerations on what our committee of experts has concluded on the quantity and quality of studies conducted to date on gestational diabetes during pregnancy:

Diverse Populations: There’s a lack of studies addressing cultural and socioeconomic differences in gestational diabetes.
Genetic and Environmental Factors: More research is needed to fully understand how these factors contribute to gestational diabetes.
Psychological Impact: The emotional effects of gestational diabetes on women are not well-studied.
Study Quality: Many studies are observational rather than randomized controlled trials, which can limit the strength of the evidence.

References

Berggren, Erica K., et al. “Racial disparities in perinatal outcomes among women with gestational diabetes.” Journal of women’s health 21.5 (2012): 521-527.
Diabetes Canada Guidelines. Diabetes Canada Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada, Diabetes Canada, 2018. https://guidelines.diabetes.ca/home.
Diabète Québec. Diabète Québec, diabete.qc.ca. Accessed June 25, 2024.
Caughey, Aaron B., Erika F. Werner, and Vanessa A. Barss. “Gestational diabetes mellitus: Obstetric issues and management.” UpToDate (online) (2022).
Institut national de santé publique du Québec. Diabète gestationnel, Institut national de santé publique du Québec, https://www.inspq.qc.ca/mieux-vivre/grossesse/sante-pendant-grossesse/grossesse-risque-eleve .
MotherToBaby. “Gestational Diabetes – MotherToBaby.” MotherToBaby, https://mothertobaby.org/fact-sheet-reference/gestational-diabetes/.
Pilliod, Rachel A et al. “The risk of fetal death in nonanomalous pregnancies affected by polyhydramnios.” American journal of obstetrics and gynecology vol. 213,3 (2015): 410.e1-6. doi:10.1016/j.ajog.2015.05.022
Society of Obstetricians and Gynaecologists of Canada. “Directive clinique N° 393 – Le diabète pendant la grossesse.” Journal of Obstetrics and Gynaecology Canada, Society of Obstetricians and Gynaecologists of Canada, https://www.jogc.com/article/S1701-2163(19)30448-7/fulltext.
Sridhar, Sneha B., et al. “Risk of Large-for-Gestational-Age Newborns in Women With Gestational Diabetes by Race and Ethnicity and Body Mass Index Categories.” Obstetrics & Gynecology, vol. 121, no. 6, June 2013, pp. 1255-1262. DOI: 10.1097/AOG.0b013e318291b15c.
Tsai, P. J. S., Roberson, E., and Dye, T. “Gestational Diabetes and Macrosomia by Race/Ethnicity in Hawaii.” BMC Research Notes, vol. 6, 2013, article 395. DOI: 10.1186/1756-0500-6-395.
Venkatesh, Kartik K., et al. “Risk of Adverse Pregnancy Outcomes among Pregnant Individuals with Gestational Diabetes by Race and Ethnicity in the United States, 2014-2020.” JAMA, vol. 327, no. 14, 2022, pp. 1356-1367.

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