What is Gestational Diabetes?

Medically reviewed by June 06, 2024| Written by

What is Gestational Diabetes?

Gestational diabetes is a type of diabetes diagnosed during pregnancy when the mother has chronically high blood sugar levels during pregnancy. It is associated with several hormonal changes in the pregnant mother’s body. 

Normally, the pancreas produces insulin, a hormone that lowers blood sugar (glucose) levels by transporting the excess sugar into cells for its breakdown and energy production. However, in gestational diabetes, the body becomesinsulin resistant i.e. insulin fails to perform its action. 

There are two types of gestational diabetes, A1 and A2. A1 gestational diabetes is not severe and you can manage the condition through diet and exercise. In contrast, A2 is a more severe form of gestational diabetes, where you need to take medicines to regulate blood sugar.

Gestational diabetes develops between24 and 28 weeks of pregnancy or in the second trimester. Increased blood glucose in pregnancy can increase the risk of Type 2 diabetes later in life for both the mother and the unborn baby. 

In severe cases, it may also increase the chances of premature birth or stillbirth. 

Having gestational diabetes doesn’t mean you had diabetes before pregnancy or will continue to have it after pregnancy. However,reports suggest that gestational diabetes increases the risk of developing type 2 diabetes later in life by twofold.

According to the American Diabetes Association, gestational diabetes affects up to10% of pregnancies in the US each year. The prevalence is high in some Asian regions, where gestational diabetes affects almost1 in 7 pregnancies.

Is Gestational Diabetes the same as Regular Diabetes?

The causes and prognosis of gestational diabetes make it different from regular diabetes.

Regular diabetes has two types,type 1 diabetes andtype 2 diabetes

In type 1 diabetes, the body produces very little or no insulin due to anautoimmune condition. Lack of insulin causes persistent increased blood sugar levels. In type 2 diabetes, the body produces a normal amount of insulin but doesn’t respond to it - making the hormone ineffective. Type 2 diabetes is mostly due to asedentary lifestyle,poor diet, and overweight/obesity.

Both types of regular diabetes are chronic conditions and have no cure. You can only manage these through medications, diet, and lifestyle changes.

In contrast, gestational diabetes is a temporary condition. It develops only due to hormonal changes in the body during pregnancy andgoes away soon after delivery. 

What are the Warning Signs of Gestational Diabetes During Pregnancy?

During the pregnancy period, a mother’s body undergoes severalphysiological changes. And so, it becomes hard for her to distinguish symptoms of gestational diabetes from signs of pregnancy. 

However, an increase in blood sugar levels during gestational diabetes can cause these symptoms:

1. Frequent Urination

Normally, the kidneys in your body filter blood and reabsorb the glucose during urine formation. Due to the high blood sugar levels in gestational diabetes, the kidneys fail to reabsorb all the glucose and pass the excess filtered glucose to the urine. 

The now highly concentrated sugary urine pulls more water into it,  causing the kidneys to excrete urine more frequently to eliminate unabsorbed glucose. This condition is also calledpolyuria and is a common symptom associated with diabetes.

2. Increased Thirst

Increased thirst or desire to drink more water in diabetes is a result of frequent urination. Since glucose gets filtered into urine in diabetes; kidneys require more water to excrete it out of the body. This increases urine volume and also the urge to urinate more. Kidneys also get additional water from other cells and tissues in the body, causing overall dehydration. 

And so, diabetes stimulates thirst and causes dry mouth. This condition is calledpolydipsia.

3. Fatigue

Studies suggest that it is common to feel tiredness and fatigue when you have diabetes, whether it is gestational or regular diabetes. There are several mechanisms by which diabetes can cause fatigue.

Your body cells use glucose as fuel to produce energy. Insulin transports glucose from the blood into the cells for the production of energy. In gestational diabetes, the cells become resistant to insulin, so there is no glucose uptake into the cells. This causeslow energy production in the cells and makes you feel fatigued.

Another explanation for fatigue in diabetes is dehydration which is caused by frequent urination to excrete excess glucose filtered into urine. 

How Does Gestational Diabetes Affect an Unborn Baby?

When a mother with gestational diabetes keeps her blood glucose levels in the normal range during pregnancy, there is little to no risk that her gestational diabetes affects the unborn baby.

However, if the mother fails to regulate her blood glucose levels in gestational diabetes, the unborn baby is at higher risk of developing several health conditions. These include: 

1. Increased Birth Weight

If the mother has high blood sugar, the baby will also have high blood sugar as the sugar can pass through the placenta. High blood sugar triggers the release of insulin in the baby, causing the processing of extra sugar.

When the supply of sugar is higher than the demand, the body of the unborn baby stores extra sugar in the form of fat, increasing the baby’s weight and size. When the baby grows more than 9 pounds during pregnancy, this condition is calledmacrosomia.

Increased birth weight can cause birth injuries, such as shoulder dystocia — damage to the shoulder when it gets stuck in the birth canal due to its larger size. 

Mothers with babies larger than average size are often advised for induced labor or cesarean section (C-section) to avoid birth complications in the baby.

2. Premature Birth

Studies show that gestational diabetes can cause premature births. Sometimes, the doctors recommend induced labor and early delivery to reduce risks during birth because of the increased size of the baby in gestational diabetes.

Premature birth is associated with severalhealth problems in the baby, such as respiratory distress syndrome and jaundice. Breathing problems are quite common in premature births, where the lungs of the baby may not be fully developed and fail to take the load soon after delivery. 

3. Hypoglycemia

In gestational diabetes, high blood sugar in the mother leads to increased blood sugar in the unborn baby. The baby tries to compensate for the high blood sugar by increasing the insulin release. 

Soon after delivery, when no sugar enters the baby’s body through the placenta as before, increased insulin levels cause the baby to have depleted blood sugar — hypoglycemia.

Research shows that long-term hypoglycemia in newborn babies can cause seizures and other brain injuries.

4. Still Birth

Stillbirth is a condition when the baby dies after 20 weeks of pregnancy in the womb. Severalstudies indicate that gestational diabetes increases the risk of stillbirth.

The uncontrolled rise in blood sugar during pregnancy can causeabnormalities in the placenta. This may disturb the regular exchange of oxygen and nutrients between mother and baby. When the condition is left untreated, it increases the risk of stillbirth.

Research shows that stillbirth can also occur due to increased baby size — a condition possible in gestational diabetes.

What is the Main Cause of Gestational Diabetes?

The exact causes of gestational diabetes are unclear, but researchers believe it is a combination of hormonal and lifestyle changes that happen during pregnancy. Gestational diabetes occurs when there are several hormonal changes in the mother’s body during pregnancy. These changes influence how the body uses insulin to regulate blood sugar and create insulin resistance.

Lactogen hormone is theprimary contributing factor to insulin resistance during pregnancy. The placenta releases lactogen to regulatemetabolism and insulin sensitivity during pregnancy.

Other hormones that can cause insulin resistance during pregnancy include growth hormone, prolactin, corticotrophin-releasing hormone, and progesterone. 

Aside from the hormonal changes, there are several other causes of gestational diabetes. Research shows that women who are obese before pregnancy have3 times higher risk of developing gestational diabetes. An increase in body weight during pregnancy can also lead to developing insulin resistance and gestational diabetes. 

Genetics also have a significant role in the incidence of gestational diabetes.Studies show that most women with gestational diabetes have at least one close family member affected by some form of diabetes.

Risk Factors

Any woman who gets pregnant is at risk of developing gestational diabetes because of hormonal changes in her body. But factors that increase the risk of diabetes include:

  1. Ethnicitycan impact the likelihood of developing gestational diabetes. Statistics show that the prevalence of gestational diabetes is highest among Southeast Asian mothers, affecting1 in 7 births. 

One theory is that Asians are more prone to abdominal fat and have low muscle mass, which increases the risk of developing insulin resistance.

  1. Being Overweight or obese before pregnancy; or gaining more than the recommended body weight during pregnancy increases therisk of developing gestational diabetes. It’s because the increase in body mass makes the cells less sensitive to insulin activity, creating insulin resistance.

Obesity also causes dysfunction in the adipose tissues — tissues that store energy in the form of fat — whichpromotes insulin resistance in the body. 

  1. Reduced Physical activitymay cause issues in regulating blood sugar levels and contribute to gestational diabetes. Research shows that women who are physically less active are at a3-fold higher risk of developing gestational diabetes compared to physically active women.
  2. High Blood Pressureincreases the risk of developing insulin resistance. Research shows that women who have high blood pressure during the 1st trimester have a 2-fold increased risk of gestational diabetes. 
  3. Polycystic Ovary Syndrome or PCOS has also been shown toincrease the risk of gestational diabetes. The explanation for this higher risk isinsulin resistance in PCOS, where a woman’s body makes adequate insulin but can’t use it effectively to regulate blood glucose.

Some other risk factors includefamily history,prediabetes, or a previous delivery of a child weighing more than 9 pounds — fetal macrosomia.


Diagnosis for gestational diabetes depends on blood tests for glucose levels. The healthcare providers perform these tests between 24 and 28 weeks of pregnancy — the incidence time of gestational diabetes. 

However, when a woman has one or more risk factors for gestational diabetes, such as obesity, family history, or gestational diabetes during a previous pregnancy, the doctor usually performs the tests at her first prenatal visit.

Tests for gestational diabetes have two parts:

a) First Glucose Challenge Test

In the first glucose challenge test, your doctor will give you a high-glucose solution to drink. After one hour, the doctor will draw your blood to test your blood sugar levels.

If the blood glucose is higher than 140 mg/dL, it indicates the risk of gestational diabetes and requires a second glucose challenge test. If your blood glucose is200 mg/dL and above in the glucose challenge test, you may have type 2 diabetes.

b) Second Glucose Challenge Test

A second glucose challenge test is only necessary if the first glucose challenge test indicates higher glucose levels than expected. In the second test, you will have to fast for at least 8 hours. 

After 8 hours, the doctor will first draw your blood as the first sample and then, give you a glucose solution to drink. The doctor will then take a sample of your blood every hour for at least three hours after you drink the solution.

High blood sugar in two or more samples confirms the diagnosis of gestational diabetes.


When diagnosed with gestational diabetes, it is crucial to keep blood glucose in the normal range to avoid pregnancy complications. And so, the aim of treatment is to manage blood glucose levels. 

In most cases, eating a healthy diet and becoming physically active are sufficient measures. However, in severe cases, you may need to take medications to regulate blood sugar levels.

1. Healthy Diet

A healthy diet in gestational diabetes means a diet of an appropriate calorie range for your body composition and stage of pregnancy, with an emphasis on high nutritional content. A dietitian can help you design a diet plan that effectively keeps your blood glucose in the normal range.

Plant-based foods are an excellent choice for gestational diabetes diets because of their fiber content. Fruits, vegetables, and whole grains are high in fiber, which reduces overall calorie consumption and preventsblood glucose spikes.

Cutting down on sugar is extremely important in the management of gestational diabetes.Studies show that sugar consumption increases the risk of developing insulin resistance. Avoid sugary drinks, artificial sweeteners, cookies, candies, and otheroverly processed foods high in added sugar.  

Once diagnosed, your doctor will likely give you a way to test your blood sugar levels. Always test for blood glucose levels after making dietary changes to see if it helps regulate blood glucose. Consult your dietitian if your diet plan isn’t effective and you continue to experience increased blood glucose.

2. Physical Activity

Studies show that women often become physically less active during pregnancy. Physical inactivity increases the severity of gestational diabetes and causes otherpregnancy complications

Physical activity helps reduce blood glucose by burning calories, reducing overall body fat, and increasing insulin sensitivity. It also helps inpreventing weight gain during pregnancy, a risk factor for gestational diabetes. 

Experts recommend 30 minutes of moderate-intensity physical activity five days a week or a total of 150 minutes a week for women with gestational diabetes. Consult your doctor to know about what physical activities are best for you during your pregnancy.

3. Medications

Medication is usually not preferred for gestational diabetes. After all, a healthy diet and physical activity are usually enough in most cases. But in some cases, these measures fail to maintain your blood glucose level in the target range, your doctor will prescribe a medication. 

Insulin is thefirst choice of diabetes medicine for gestational diabetes as it doesn’t cause harm to the baby. Your doctor will prescribe you the insulin dosage you need, and you must strictly follow instructions. 

Taking a lower dosage than recommended will not effectively reduce blood glucose. And if you take a higher dose, it will cause an abnormal drop in blood glucose — hypoglycemia.

Oral medications such as metformin and glyburide lack FDA approval for use in gestational diabetes. However,studies show that the use of oral medications is increasing among women with gestational diabetes. 

Can Diet and Lifestyle Changes Prevent Gestational Diabetes?

Studies show that with a change in diet and moderate exercise, women can prevent gestational diabetes. The goal of diet and lifestyle changes is to eat fewer foods that will spike your blood sugar like refined carbohydrates and stay physically active, keeping the overall blood glucose low.

Pregnant women are supposed to eat more and gain weight during pregnancy. However, there is alimit to how much weight gain is normal and healthy, and you must avoid gaining weight above that limit.

Obesity is thought to be one of the major causes of gestational diabetes, as it increases insulin resistance. Eat a balanced diet before and during pregnancy to avoid weight gain that is above your recommended weight gain for pregnancy. 

Lifestyle changes include becoming physically active before and during the pregnancy.Statistics show that the incidence of gestational diabetes is lower among physically active mothers. 

Physical activity helps with weight management, and a healthy weight can prevent you from gestational diabetes and other pregnancy complications.

What foods to Eat for Gestational Diabetes?

If you have gestational diabetes, you must plan your diet wisely and choose healthy foods. Your diet decides your blood glucose levels in gestational diabetes and influences the health of the mother and baby.

Healthy foods to eat for gestational diabetes include:

1. Non-starchy Vegetables

Non-starchy vegetables are low in carbs but contain a variety ofvitamins and minerals. They are also fiber-rich, meaning you can eat plenty without an abrupt increase in blood glucose.

 Examples of non-starchy vegetables are:

  • Broccoli
  • Cabbage
  • Carrots
  • Green beans
  • Onions
  • Salad green

2. Lean Proteins

Lean proteins are low in fats and calories. They enhance feelings of satiety by making you feel full. Lean proteins are also thebuilding blocks for the growth of a baby.

Lean proteins include:

  • Chicken
  • Eggs
  • Fish
  • Low-fat dairy

3. Healthy Fats

Although fats are rich in calories,not all fats are bad for you. Healthy fats help to control blood pressure and make you feel full, thus helping in gestational diabetes.

Healthy fat sources include:

  • Avocado
  • Nuts
  • Olive oil
  • Seeds

4. Healthy Carbohydrates

In gestational diabetes, you should limit refined carbohydrates and instead opt for complex carbohydrates. Complex carbohydrates contain fiber and don’t cause an abrupt elevation in blood glucose. They serve as an energy source and provide healthy nutrients to your body.

You can get healthy carbohydrates from:

  • Beans
  • Fiber-rich fruits
  • Fibre-rich vegetable
  • Legumes
  • Whole grains


  • Is Gestational diabetes high-risk?
  • Gestational diabetes is a high risk in pregnancy if the mother fails to regulate her blood glucose. It can cause birth complications and long-term problems, such as an increased risk of type 2 diabetes later in life.

  • Can You Have a Normal Baby with Gestational Diabetes?
  • You can have a normal baby with gestational diabetes if you manage to control your blood glucose in the normal range. You can do so by adopting the necessary diet and lifestyle changes your healthcare provider recommends.

  • Will Gestational Diabetes Cure Itself After the Baby’s Birth?
  • Gestational diabetes is primarily due to hormonal changes during the pregnancy and goes away soon after the baby’s birth. If you are experiencing increased blood glucose even after delivery, you most probably have type 2 diabetes.

  • Will My Baby be Diabetic if I develop Diabetes During Pregnancy?
  • A newborn baby from a mother with gestational diabetes is usually not diabetic. However, uncontrolled blood glucose levels in the mother during pregnancy increase the risk of developing diabetes in their babies later in their lives.


    Gestational diabetes affects up to 10% of pregnancies around the world each year. It happens because of the hormonal changes during pregnancy that can cause insulin resistance and increased blood sugar levels in the mother.

    A mother only needs to regulate her blood glucose levels during pregnancy, as gestational diabetes goes away soon after the delivery. But if she doesn’t manage her glucose levels, it can cause birth complications and long-term problems for the mother and the baby. 

    Changes in diet and increasing physical activity are usually enough to maintain blood glucose levels. Severe cases may need prescription medicines. However, eating a healthy diet and adopting a healthy lifestyle before and during pregnancy can prevent you from developing gestational diabetes.