Is Gestational Diabetes Genetic?

Up to 14% of pregnancies in the United States¹ are affected by gestational diabetes mellitus (GDM). This is a type of diabetes seen only in pregnant women and that, in most cases, goes away shortly after delivery.

Along with other types of diabetes, gestational diabetes is becoming more common. If left untreated, it can have long-term negative effects on the health of both the mother and baby. But with early intervention, close monitoring, and treatment, a mother with gestational diabetes can have a healthy pregnancy and deliver a healthy baby.

While it's not clear why some people develop GDM and others do not, there does appear to be a genetic link. If an immediate family member has been diagnosed with diabetes, you may be more likely to develop gestational diabetes.

It's important to understand what gestational diabetes is, what signs to watch for, and how your family history could play a role in increasing your risk of developing the disease.

What is gestational diabetes?

Gestational diabetes is a type of diabetes that occurs during pregnancy. It can develop at any point in the pregnancy but is most commonly seen in the second and third trimesters. The condition is due to a combination of insulin resistance and your body not being able to produce enough insulin to keep up with increased demand.

Your body uses insulin to move glucose (sugar) out of your bloodstream and into your cells, where it's used as energy. When your body doesn't have enough insulin or becomes insulin resistant, the result is an increase in your blood glucose levels.

If left untreated, high blood sugars harm the health of both mother and child. Mothers with GDM will also be at an increased risk of developing type 2 diabetes later in life and are more likely to have infants with congenital disorders. Their infants are also more likely to have high birth weights, which increases the likelihood of a C-section delivery and the risk of birth injuries and congenital disorders.

Gestational diabetes can also increase the risk of premature birth.  Newborns of mothers with poor glucose control may experience a crash in their glucose levels within the first few hours after delivery.

Gestational diabetes is a treatable condition, and many people can manage their blood sugar levels by changing their diet and increasing the amount of exercise they get daily. In some cases, oral medication or injectable insulin will also be needed to keep glucose levels in check.

Causes of gestational diabetes

Gestational diabetes develops due to hormonal changes in the body during pregnancy. Your placenta will produce a hormone that makes you more insulin resistant. This is to help direct more of the glucose in your bloodstream to be taken through the placenta directly to your baby. Your insulin resistance will go up in the later stages of the pregnancy, especially in the last trimester, when a lot of your baby's growth occurs.

Usually, the pancreas can overcome insulin resistance by simply increasing the amount of insulin it is producing. This helps maintain healthy blood sugar levels for both mother and baby. When the body cannot produce enough insulin to overcome insulin resistance, it results in gestational diabetes.

Researchers don't have a definitive answer for why some people can overcome insulin resistance during pregnancy while others are not. There are associations seen between maternal weight before pregnancy and lifestyle choices.

Genetic factors also impact your risk, which is higher if your close family members have type 2 diabetes.

Signs and symptoms of gestational diabetes

Some women who develop gestational diabetes may not experience any physical symptoms of the condition, especially in the early stages of the disease. However, common symptoms of diabetes include:

• Increased thirst or drinking more than usual

• Frequent need to urinate

• Feeling more tired than usual

• Blurred vision

• Nausea 

• Developing infections in the skin, bladder, or vagina

Signs of gestational diabetes may not always be obvious. They may present as symptoms commonly associated with pregnancy, such as fatigue and nausea, making it easy to dismiss them. It's important to mention all symptoms to your primary care physician during your appointments. Your symptoms may indicate GDM or another underlying health concern. 

How will I know if I have gestational diabetes?

Your doctor can test for and diagnose gestational diabetes. Lab tests are the only definitive way to determine if you have the condition. Doctors routinely screen for gestational diabetes between the 24th and 28th weeks of pregnancy, when the condition is most likely to occur.

However, it's possible to develop gestational diabetes at any time during your pregnancy.

If you start to experience any new or unusual symptoms, let your doctor know. The earlier gestational diabetes is detected, the better your doctor can help you manage it through the rest of your pregnancy.

Keeping your blood sugars within a healthy range will improve the outcome for both you and your baby.

To diagnose gestational diabetes, your doctor may request:

Urine test

Diabetes causes a rise in your blood sugar levels, and your body disposes of extra glucose through your urine.  A urine sample can be tested for glucose, and if it is present, this could indicate gestational diabetes.

1-hour glucose challenge screening

This test starts with a blood draw to determine your baseline blood sugar level. You'll then drink a syrupy substance that contains a predetermined amount of glucose. After about an hour, you will have another blood draw. If your blood sugar level is above the acceptable range, your body isn't producing enough insulin to overcome your insulin resistance when given glucose. That could mean that you have gestational diabetes.

3-hour glucose tolerance test

If your screening tests are abnormal, your doctor will require you to fast overnight before returning to the doctor's office. You'll be given a higher dose of glucose to drink, and then blood samples will be obtained over 3 hours. Your doctor will use these test results to determine if your body produces enough insulin.

If you are diagnosed with gestational diabetes, your doctor will work with you to develop a treatment plan. The treatment will include lifestyle changes, such as changing your diet and getting more exercise.

Your doctor may also recommend medication to bring your blood sugar levels into the normal range. With the right treatment and care, many people with gestational diabetes go on to have healthy pregnancies and deliver healthy babies. 

Who is at risk of getting gestational diabetes?

Anyone can develop gestational diabetes. However, certain factors may increase your risk of developing the disease. You may be at a greater risk of GDM if you are:

Pregnant after the age of 35

The risk of developing gestational diabetes increases along with maternal age.

Obese

Being obese can greatly increase your risk. Starting your pregnancy at a healthy body weight may reduce this risk.

Have a first-degree relative with diabetes

Genetic background of insufficient insulin secretion and insulin resistance impacts your risk of developing gestational diabetes.

Had GDM with a previous pregnancy

You'll have about a 50% chance² of developing the condition with future pregnancies.

Certain environmental factors could also increase your risk, as discussed below.

Is gestational diabetes genetic?

Researchers are still trying to understand why some people develop gestational diabetes while others do not. It seems the disease may be due to both genetic and environmental factors.

Research shows that GDM shares many genetic markers with type 2 diabetes. Both diabetes types are due to insulin resistance, and there are several genes associated with increasing the risk of insulin resistance observed in both type 2 diabetes and GDM.

That means people with these specific genes would be more likely to develop gestational diabetes and type 2 diabetes. This could help explain why so many women who develop GDM during pregnancy develop type 2 diabetes later in life.

Having these genes doesn't guarantee that you'll develop either type of diabetes. Lifestyle choices such as having a healthy, balanced diet and getting plenty of exercise can reduce the risk of developing either type of diabetes, despite your genetic makeup. Even if you have the specific genetic markers for GDM, it may be possible to prevent it from developing during your pregnancy with the right interventions.

Researchers continue to look into the link between gestational diabetes and your genes. New sequencing methods will help identify genetic markers that increase a person's risk of developing the disease. That information could help doctors develop more specific screening tests for GDM and more accurately predict who is most likely to develop the condition.

Appropriate interventions could then be implemented for anyone genetically predisposed to the condition. Doing this could help more mothers and babies avoid the complications associated with gestational diabetes in the future. 

Does family history cause gestational diabetes?

Your family's health history won't directly cause gestational diabetes, but it could put you at increased risk.

Research suggests that people who have close family relatives with type 2 diabetes are more likely to develop GDM. If you have a parent with type 2 diabetes, you are 2.3 times more likely to develop gestational diabetes.³ If your sibling has type 2 diabetes, you are 8.4 times more likely to develop the condition during pregnancy.

You are also eight times more likely to develop gestational diabetes if your mother had it during her own pregnancy. So research does indicate that gestational diabetes runs in families.

Along with genetic predisposition, your family may also influence lifestyle choices that impact your risk. If you grew up in a family in which eating a high-sugar, high-fat diet was the norm, you might continue to eat this type of diet as an adult. This increases your risk of obesity, which leads to an elevated risk of developing both type 2 and gestational diabetes.

Likewise, you may have inherited a love for exercise from your family. That could lower your risk for gestational diabetes by helping your body naturally balance your blood sugar levels.

Letting your doctor know about your family's health history with diabetes will help them more accurately predict your own risk of developing the condition. If you have a family history of diabetes, your doctor may decide to monitor your blood sugar levels more closely throughout your pregnancy. 

What environmental factors affect diabetes risks?

Along with genetic factors, environmental and lifestyle factors can also increase your risk of developing gestational diabetes. These include:

Diet

Balanced diets high in fiber and low in refined carbohydrates can help reduce your risk of developing GDM. High-fiber diets that focus on complex carbohydrates (beans, vegetables, whole grains) instead of simple carbohydrates (sugar, candy, soda, highly processed foods) can help increase insulin sensitivity and boost glucose utilization.

Depression and anxiety

Mothers experiencing depression and anxiety are more likely to develop gestational diabetes. These mental health conditions and the stress that accompanies them cause increased cortisol production, contributing to increased blood sugar levels and insulin resistance.

Sedentary lifestyle

A lack of daily physical activity can increase your risk of developing gestational diabetes, while increased activity levels can help lower the risk. Exercise works to balance your blood sugar naturally, so it can reduce your reliance on insulin.

Vitamin D deficiency

A lack of vitamin D can increase your risk of gestational diabetes. Taking a vitamin D supplement can help protect you from developing the condition, especially if you have a high BMI.

Warm temperatures

Some research suggests that there may be a link between the temperature of the environment you are in and your risk of developing GDM. One study found that gestational diabetes was more common in the summer months, with evidence linking hotter ambient air temperatures and higher glucose levels.

Air pollution

Evidence suggests that exposure to air pollution⁴ can increase your risk of developing gestational diabetes. However, more research is needed to determine why air pollution increases the risk.

It's important to remember that while all these factors can increase your risk of developing gestational diabetes, many of them are just associations with no guarantee that they will impact you. You can help lower your risk by maintaining a healthy, balanced diet and getting at least 30 minutes of moderate exercise a day

If you have concerns about your risk of gestational diabetes, talk to your doctor about preventative care strategies.

Treatment and prevention of gestational diabetes

Gestational diabetes is a manageable condition. With the right treatment plan, you can keep your blood sugar levels in a healthy range and avoid the complications associated with the disease. If you are diagnosed with GDM, your healthcare professional will work with you to develop a treatment plan that considers your age, lifestyle, and medical condition.

Some of the treatment options include:

Monitoring blood sugar levels

Your doctor will have you monitor your blood sugar levels at home to ensure they stay within a normal range. You'll do this by pricking your finger with a lancet and placing a small drop of blood on a glucose meter. By consistent tracking, you can determine when your blood sugar levels are getting too high and take quick action to bring them back into a normal, healthy range.

Changing your diet

If you have GDM, your doctor may recommend a low-carbohydrate, high-fiber diet. Limiting carbohydrates can keep your blood sugar levels in a healthy range. Avoid high-glycemic, high-fat, and processed foods in favor of whole, fiber-rich, nutrient-dense foods. You should also avoid added sugars, such as soda, candy, and baked goods.

Exercising regularly

Exercise is a great way to help naturally manage your blood sugar levels. You should always check with your doctor about starting a new exercise routine, especially when pregnant. In most healthy pregnancies, it's safe and beneficial to incorporate mild to moderate aerobic exercise into your day. Consider walking, swimming, or joining a pregnancy-focused fitness or yoga class.

Starting medication

When diet and exercise aren't working to regulate your blood sugar levels, your doctor may recommend that you take medication. There are oral medications and insulin that can be injected at home, and your doctor will determine which will work best for you. You will need to continue to monitor your blood sugar levels throughout the pregnancy to ensure you are getting the right amount of medication.

In some cases, it may be possible to prevent gestational diabetes. While genetics certainly plays a role, becoming pregnant when you are overweight or obese does increase your risk. You may be able to improve this by losing weight before you get pregnant and maintaining a healthy, balanced diet that's low in added sugar and carbs, along with getting at least 30 minutes of exercise a day.

The lowdown

Gestational diabetes occurs during pregnancy. It is caused by the inability to produce enough insulin to compensate for the effects of hormonal changes during pregnancy. Approximately 14% of pregnancies are affected by it, along with type 2 diabetes.

Doctors routinely screen for GDM between the 24th and 28th weeks of pregnancy, when it's most likely to develop. Because pregnancy and high blood sugars often accompany increased thirst and fatigue, it may be difficult to identify diabetes during pregnancy.

Researchers still aren't sure why some people develop gestational diabetes while others do not, but both genetic and environmental factors are at play. You might also be at increased risk of gestational diabetes if a close family member has been diagnosed with type 2 diabetes or your mother had gestational diabetes while she was pregnant.

Other factors that increase the risk of GDM include a high BMI, poor diet, lack of exercise, previous pregnancy with the condition, and increased maternal age. Air pollution and warm air temperatures may also play roles in increasing risk.

Gestational diabetes is a manageable condition, usually treated through diet and exercise. In some cases, oral medication or insulin injections will also be needed to control blood sugar levels during pregnancy.

For most women, the condition will resolve on its own after delivery. However, both mother and baby will be at risk of developing type 2 diabetes later in life, so it is important to let your health care professional know if you've ever had GDM. With early detection and the right treatment, it's possible to have a normal pregnancy and deliver a healthy, full-term baby.