Gestational Diabetes: Symptoms, Causes, Diagnosis & Treatment

Symptoms are similar to non-gestational diabetes, yet the causes are different.

Medically reviewed by Dr. Karla S. Sanchez-Banos, MD Dr. Karla S. Sanchez-Banos Dr. Karla S. Sanchez-BanosMD facebook_iconinsta_icon Specialty: Obstetrics and Gynecology, Children and Adolescent GynecologyExperience: 11 years
Written by Swati Patwal
Last Updated on

Gestational diabetes (GDM) occurs in pregnant women who are non-diabetic before conception. During pregnancy, the hormonal changes paired with the weight gain may affect the blood insulin’s effectiveness in controlling the blood sugar levels. This switch may cause insulin resistance in a few women, leading to gestational diabetes (1).

Fortunately, GDM can usually be managed with an active lifestyle and healthy eating habits during pregnancy. But sometimes, a few women may need insulin treatment. This is also short-lived since GDM resolves after the baby’s birth (2).

Read on to know about the management of GDM, its symptoms, risk factors, diagnosis, and treatment.

Symptoms Of Gestational Diabetes

GDM doesn’t cause any signs and symptoms in most pregnant women. Yet, there are a few symptoms that you mustn’t ignore and get your blood sugar level tested (3)(4).

  • Unusual thirst
  • Frequent urination
  • Fatigue
  • Nausea
  • Frequent infections of the skin, vagina, and bladder
  • Blurred vision

If you have these symptoms, talk to your doctor and ask to get tested for gestational diabetes. According to the American Diabetes Association (ADA), “nearly ten percent of pregnancies in the US are affected by gestational diabetes every year.”(5)

Causes Of Gestational Diabetes

There isn’t an exact cause why some non-diabetic women develop gestational diabetes during pregnancy while others don’t. However, here’s a plausible reason that could offer some explanation (4)(6).

During pregnancy, the placenta acts as the source of nourishment for the fetus and produces hormones to maintain pregnancy. But, some of these hormones, such as estrogen, cortisol, and human placental lactogen, can block insulin functioning (contra-insulin effect), triggering insulin resistance. Insulin is a hormone produced by the beta-cells of the pancreas that helps the body’s cells absorb glucose, regulating blood sugar levels.

At first, the mother’s body produces more insulin to overcome insulin resistance. But, as the pregnancy progresses, insulin production fails to overcome the contra-insulin effect, resulting in gestational diabetes. Several risk factors raise a pregnant woman’s chances of developing GDM. The next section gives an insight into them.

Risk Factors For Gestational Diabetes

According to the Centers for Disease Control and Prevention (CDC), some pregnant women have insulin resistance before pregnancy, raising their chance of developing GDM (7). Besides this, the other risk factors for GDM are (2):

  • Age above 25 years
  • Family history of diabetes
  • Overweight or obesity
  • Physical inactivity during pregnancy
  • Gestational diabetes in the previous pregnancy
  • Previously delivering a baby weighing more than nine pounds
  • Previous unexplained miscarriage or stillbirth
  • Intake of certain medications, such as glucocorticoids
  • Presence of chronic health issues, such as polycystic ovarian syndrome (PCOS), high blood pressure, and heart disease

Some women may have type-1 or type-2 diabetes before they conceive. Although the etiology of both types of diabetes varies, both raise the risk of GDM.

According to John Hopkins Medicine, women of certain gene pools, such as Hispanic, Native American, Asian American, and African-American, may have a higher risk of developing gestational diabetes (6).

Diagnosis Of Gestational Diabetes

Insulin resistance (contra-insulin effect) usually begins between the 20th and 24th week of pregnancy(6). Therefore, all pregnant women are tested for gestational diabetes during a routine checkup between the 24th and 28th week of pregnancy as a part of prenatal care (3). If a woman has risk factors for gestational diabetes, a doctor may test for GDM earlier in the pregnancy.

The doctor will perform the following blood tests to diagnose gestational diabetes (8) (9):

1. Glucose challenge test

It’s the first test that the doctor will perform to diagnose GDM. For the test, the doctor will ask you to drink a sweet liquid containing 50g of sugar/glucose. Then, after an hour, they will run a blood test to measure your blood sugar level.

If your blood sugar level is greater than or equal to 140mg/dL (7.8 mmol/L), the doctor will order the oral glucose tolerance test. If your sugar level is greater than equal to 200mg/dL, you may have type-2 diabetes.

2. Oral glucose tolerance test (OGTT)

Unlike the glucose challenge test, the OGTT measures fasting and non-fasting glucose levels. The test first requires you to fast for at least eight hours. Then, your healthcare professional will take your blood sample and give you a sweet liquid containing 75g of sugar/glucose dissolved in 300 ml of water to drink.

The doctor will check your sugar level every hour for two to three hours. If any two or more readings (fasting, one hour, or two hours) are higher than or equal to the values shared below, it indicates you have GDM.

MealtimeBlood Sugar Levels (mg/dL)
After fasting92
After one hour180
After two hours153

Source: National Center for Biotechnology Information (NCBI)

Glucose testing at the first prenatal visit is recommended if a woman has one or more diabetes risk factors. In some cases, the doctor may also advise urinalysis to test glucose in the urine, indicating gestational diabetes.

Management And Treatment For Gestational Diabetes

Most women can manage gestational diabetes with healthy eating, an active lifestyle, and medication (if necessary) (10).

1. Healthy eating

Women with GDM should follow a personalized diet plan based on their sugar levels, activity levels, and overall health. A diet expert or certified nutritionist will help you plan a well-balanced diet plan with details, such as what to eat, how much to eat, and when to eat. Besides, they can ask you to:

  • Space your meals at regular intervals and eat every two to three hours. It’s a vital step while eating carbs, as spacing out carb-rich foods helps control sugar levels.
  • Eat more complex carbs, such as whole grains, low-sugar fruits, and starchy veggies.
  • Eat two to three servings of high-quality protein foods, such as fatty fish, non-fat or low-fat dairy, lean meat, and soy products, such as tofu.
  • Include heart-healthy, omega-3-rich foods, such as avocado, unsalted nuts, seeds, and olive oil.

Women with GDM are at a high risk of developing type-2 diabetes during their lifetime. Hence, healthy eating is vital to maintain a healthy weight and safe sugar levels during and after pregnancy.

2. Active lifestyle

Indulging in moderate-intensity physical activity or exercise for 30 minutes, five days a week, can help keep your sugar levels within the desired target range. Besides, it can also help relieve stress, strengthen muscles, and keep joints flexible. Speak to your doctor about the appropriate activities based on your health and pregnancy stage. Generally, walking ten to 15 minutes after each meal can help have better blood sugar control.

3. Medication

Healthy dietary and lifestyle changes can help manage blood sugar levels within recommended limits for most women. However, if these changes don’t prove effective, you may need oral hypoglycemic drugs or insulin. Your doctor will guide you on a suitable medication/insulin course. They will also teach you the way to self-inject insulin. Injectable insulin is safe as it doesn’t cross the placenta and doesn’t affect the baby (2).

4. Monitor sugar levels

Regular monitoring of sugar levels is vital for the effective management of GDM. Use a glucometer to monitor your blood sugar levels at different intervals throughout the day. Note the readings in a diary or your phone and maintain a track that you and your doctor can check to evaluate if your diabetes management plan is working.

Here are the daily target blood glucose levels for most women with GDM (10).

MealtimeTarget Sugar Levels (mg/dL)
Before meals, at bedtime, and overnightLess than or equal to 95
One hour after eatingLess than or equal to 140
Two hours after eatingLess than or equal to 120

Source: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Based on your overall health and BMI, your doctor will decide on individualized blood sugar targets for you. To attain and maintain those targets, you should diligently follow your diet, activity, and medicine schedules.

Experts recommend testing sugar levels for six weeks after delivery for women with GDM. If the sugar levels are normal, the doctor will order a re-evaluation after a year. However, if the sugar levels are abnormal, your doctor may provide guidance on diabetes management and prevention.

Possible Complications Of Gestational Diabetes

In gestational diabetes, there’s more sugar in the mother’s blood. This excess sugar passes to the fetus, causing them to gain excess weight. Generally, a fetal weight of nine pounds (four kilograms) or more could cause complications for the mother and the baby. Here’s a brief overview of those complications (11)(12).

1. High blood pressure (HBP) and preeclampsia

HBP or hypertension during pregnancy can put undue stress on a mother’s circulatory system. As a result, she may develop preeclampsia, a condition where the mother’s organs, such as kidneys and liver, may not work properly. Some of the signs of preeclampsia an expecting mom may exhibit are:

  • Proteinuria (protein in the urine)
  • Vision changes
  • Severe headaches

HBP and preeclampsia can increase the risk for preterm birth.

2. Macrosomia

GD causes high maternal blood sugar levels, causing babies to gain more weight. Gaining too much weight (nine or more pounds) can cause the baby to get stuck in the birth canal. It can lead to birthing difficulties, such as a severe tear to the vagina or area between the vagina and anus (if it’s a vaginal delivery). Alternatively, in some cases, the mother may require a cesarean section (C-section).

3. Shoulder dystocia

It’s a birth injury/trauma where a baby’s shoulders get stuck inside the mother’s pelvis during labor and birth. It can lead to complications, such as prolonged labor and severe injuries to the mother and baby.

Shoulder dystocia could cause postpartum hemorrhage (excessive bleeding) in mothers. On the other hand, the babies could have collarbone and arm fractures. They may also experience damage in nerves responsible for giving sensation and movement to the hands, shoulders, and arms.

4. Perinatal depression

Perinatal depression is the depression that a mother could develop during or a year after pregnancy (postpartum depression). It affects up to 20 percent of new and pregnant moms (13). A mother with depression feels sad, apathetic, and irritable, making it difficult to bond with the baby. The condition may require treatment for the well-being of the mother and the baby.

5. Congenital disabilities

Babies born to diabetic mothers are more likely to have birth defects, affecting major organs and physiological systems, such as the heart, blood vessels, brain, spine, and digestive system. According to Stanford Children’s Health, birth defects usually occur in the first trimester of pregnancy and can be severe enough to cause stillbirth.

6. Hypoglycemia

High maternal blood sugar levels make the baby’s sugar levels rise, compelling the baby’s body to make more insulin. However, the baby’s blood sugar levels fall after delivery. However, the insulin levels continue to stay high. As a result, the newborn’s blood glucose level falls too low, resulting in hypoglycemia.

7. Breathing problems

Too much sugar or insulin can hamper the baby’s intrauterine lung development. Underdeveloped lungs pose the risk of breathing problems, such as respiratory distress syndrome (RDS). Babies born before 37 weeks of pregnancy (preterm) are at a higher risk of developing breathing problems than those born after 37 weeks (full-term).

8. Jaundice

Yellow coloration of the skin and pupils of the eyes are common signs of jaundice. Babies born to mothers with gestational diabetes are more likely to develop jaundice than those born to mothers who don’t have GDM.

Besides these potential complications, the child is at risk of developing obesity and diabetes later in life.

Is Gestational Diabetes Preventable?

You can’t prevent gestational diabetes. But, you can reduce the chances of developing it by following healthy lifestyle practices, such as healthy eating and an active lifestyle before and during pregnancy. If you are planning to conceive and are overweight/obese, lose weight first by adopting healthy lifestyle habits.

On the other hand, if you are pregnant, don’t try losing weight. Instead, track your weight changes and keep them within the recommended target limits. For this, take the help of an expert, such as a nutritionist, to manage your weight. Remember, gaining too much weight too quickly can expose you to gestational diabetes risk.

Frequently Asked Questions

1. What should I avoid eating with gestational diabetes?

You should avoid simple carbohydrates when dealing with gestational diabetes (14). Food items with such carbohydrates include white rice, potatoes, desserts, and soda.

2. Is gestational diabetes an indicator of a high-risk pregnancy?

Gestational diabetes may increase the risks of preeclampsia, which can lead to other complications. Therefore, women with gestational diabetes might need care similar to high-risk pregnancies (15).

3. Are eggs good for gestational diabetes?

Yes. You may consume eggs for gestational diabetes. But ensure that the eggs are cooked fully until the yolk and outer layer are firm (16).

4. What week does gestational diabetes peak?

Gestational diabetes usually peaks at about 26-33 weeks of pregnancy. It mostly happens as the insulin resistance effect of estrogen and cortisol is seen to be the highest during this period (17).

5. Would my child get diabetes if I had gestational diabetes?

It has been reported that children are six times more likely to develop diabetes in cases where the mother is affected by gestational diabetes (18).

6. Can gestational diabetes cause autism?

A study noted that babies exposed to gestational diabetes in the womb during the 28-44 weeks of pregnancy had a high risk of being diagnosed with autism spectrum disorder (ASD) (19). However, not all babies born to mothers with gestational diabetes develop ASD, and more research is needed to establish a definitive correlation.

7. How common is stillbirth with gestational diabetes?

Gestational diabetes may increase the risk of stillbirth. However, more research is needed to determine the underlying cause. The risk of stillbirth can be reduced if the woman practices good glucose control to manage diabetes (20).

Gestational diabetes is a condition when a non-diabetic pregnant woman develops high blood sugar levels. The exact cause for its development isn’t clear, but hormonal and weight changes during pregnancy play a role. Most women can manage gestational diabetes by following a healthy diet and active lifestyle habits. However, some may also need medication to ensure their sugar levels are under control.

Key Pointers

  • Unusual thirst, frequent urination, nausea, exhaustion, and recurrent infections are common symptoms of gestational diabetes.
  • Some of the hormones released by the placenta might sometimes interfere with insulin activity, resulting in GDM.
  • Between the 24th and 28th week of pregnancy, all pregnant women are tested for gestational diabetes as part of prenatal care.
  • Gestational diabetes may cause macrosomia, shoulder dystocia, jaundice, congenital disabilities, and breathing difficulties.


  1. Gestational Diabetes and Pregnancy.
  2. Gestational Diabetes.
  3. Gestational Diabetes.
  4. Symptoms & Causes of Gestational Diabetes.
  5. Gestational Diabetes.
  6. Gestational Diabetes Mellitus (GDM)
  7. Gestational Diabetes.
  8. Tests & Diagnosis for Gestational Diabetes.
  9. How is gestational diabetes diagnosed?.
  10. Managing & Treating Gestational Diabetes.
  11. Gestational Diabetes.
  12. Diabetes During Pregnancy.
  13. Perinatal mental health.
  14. Gestational diabetes diet.
  15. Gestational Diabetes: Managing Risk During and After Pregnancy.
  16. Meal ideas for gestational or type 1 or 2 diabetes in pregnancy.
  17. Malik Mumtaz; Gestational Diabetes Mellitus.
  18. children six times more likely to develop type 2 diabetes if mother has gestational diabetes
  19. Anny H. Xiang et al.; Association of Maternal Diabetes With Autism in Offspring.
  20. Diabetes During Pregnancy.
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Dr. Karla S. Sanchez-Banos is a board-licensed Ob/Gyn in Mexico, specializing in Adolescent Gynecology. She is also trained in Gynecological Endocrinology, granted by AMEGIN (Gynecological Endocrinology Mexican Association).

Read full bio of Dr. Karla S. Sanchez-Banos
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