In health and wellness, certain conditions deserve our attention for the unique ways they affect individuals, especially those expecting a child. One such condition is gestational diabetes. This article aims to demystify the concept of gestational diabetes, explaining its distinct nature compared to other types of diabetes.

What Is Gestational Diabetes?

During pregnancy, some women experience a temporary hiccup in regulating blood sugar levels, leading to a condition known as gestational diabetes. This means that blood sugar levels rise higher than usual, potentially posing risks to both the mother and the baby.
Gestational diabetes typically arises during the second or third trimester of pregnancy when hormonal shifts make the body more insulin-resistant. Insulin, the key that unlocks cells to allow sugar to enter, is crucial in maintaining healthy blood sugar levels. When the body struggles to use insulin effectively, sugar accumulates in the bloodstream, potentially causing complications.

How Does Gestational Diabetes Differ From Other Types of Diabetes?

Gestational diabetes is a type of diabetes that occurs during pregnancy in women who did not previously have diabetes. It is characterised by high blood sugar levels that develop during pregnancy and usually resolve after childbirth. Gestational diabetes is distinct from other types of diabetes, such as type 1 diabetes and type 2 diabetes, in several key ways:

Onset and Occurrence

  • Gestational Diabetes – This type of diabetes develops specifically during pregnancy and is absent before conception. It typically occurs around the 24th to 28th week of pregnancy.
  • Type 1 Diabetes – This is an autoimmune condition in which the body’s immune system attacks and destroys insulin-producing cells in the pancreas. It can develop at any age and is usually diagnosed in childhood or young adulthood.
  • Type 2 Diabetes – This is a metabolic disorder in which the body becomes resistant to insulin or does not produce enough insulin to maintain normal blood sugar levels. It is often associated with obesity, a sedentary lifestyle, and genetic predisposition.


  • Gestational Diabetes – The exact cause is not fully understood, but hormonal changes during pregnancy can lead to insulin resistance, where the body’s cells do not respond effectively to insulin. This results in elevated blood sugar levels.
  • Type 1 Diabetes – It is primarily caused by an autoimmune response that targets and damages insulin-producing cells in the pancreas.
  • Type 2 Diabetes – It is influenced by a combination of genetic factors, lifestyle factors (such as diet, physical activity, and obesity), and insulin resistance.

Long-Term Effects

  • Gestational Diabetes – Blood sugar levels usually return to normal after childbirth. However, women with gestational diabetes have an increased risk of developing type 2 diabetes later in life.
  • Type 1 Diabetes – It requires lifelong insulin therapy and management. If not properly managed, it can lead to complications affecting the heart, kidneys, eyes, nerves, and other organs.
  • Type 2 Diabetes – If left unmanaged, it can lead to various complications similar to those of type 1 diabetes, including cardiovascular disease, kidney problems, nerve damage, and eye issues.


  • Gestational Diabetes – It is typically managed through dietary changes, regular physical activity, and, in some cases, insulin therapy to control blood sugar levels during pregnancy.
  • Type 1 Diabetes – It requires insulin therapy for life, along with careful monitoring of blood sugar levels, diet, and physical activity.
  • Type 2 Diabetes – Treatment may involve lifestyle changes (diet and exercise), oral medications, and in some cases, insulin therapy.
Gestational diabetes is a temporary form of diabetes that occurs during pregnancy. In contrast, type 1 and type 2 diabetes are chronic conditions that can persist beyond pregnancy and have different causes, risk factors, and management approaches. Pregnant women need to receive proper prenatal care, including screening for gestational diabetes, to ensure the health of both mother and baby.

What Are the Causes of Gestational Diabetes?

The exact causes of gestational diabetes are not fully understood, but several factors are believed to contribute to its development. Gestational diabetes occurs when the body becomes less sensitive to insulin or does not produce enough insulin to maintain normal blood sugar levels during pregnancy. Some of the key factors that can contribute to the development of gestational diabetes include:

Hormonal Changes

During pregnancy, the placenta produces hormones that help the baby grow and develop. Some of these hormones can interfere with the body’s ability to use insulin effectively, leading to insulin resistance. Insulin resistance means that the body’s cells do not respond well to the insulin produced, causing blood sugar levels to rise.

Increased Insulin Resistance

Pregnancy naturally increases insulin resistance, particularly in the second and third trimesters. This is a normal physiological response to ensure enough glucose is available for the growing fetus. However, in some women, this increased resistance can lead to gestational diabetes if their pancreas cannot produce enough insulin to compensate.

Genetic Predisposition

A family history of diabetes, particularly type 2 diabetes, can increase the risk of developing gestational diabetes. Genetic factors affect how the body responds to insulin and manages blood sugar levels.

Obesity and Excess Weight Gain

Women who are overweight or obese before pregnancy are at a higher risk of developing gestational diabetes. Excess body weight can contribute to insulin resistance, making it more difficult for the body to regulate blood sugar.


Women who are older when they become pregnant, especially those over 25, have a higher risk of gestational diabetes.
While these factors can increase the risk of gestational diabetes, not all women with these risk factors will develop the condition. Regular prenatal care, including screening for gestational diabetes, can help identify and manage the condition to ensure the health of both the mother and the baby.

What Are the Risk Factors Associated With Gestational Diabetes?

Several risk factors are associated with an increased likelihood of developing gestational diabetes during pregnancy. These risk factors can help doctors identify women who may be at a higher risk and require closer monitoring or screening. It’s important to note that having one or more risk factors does not guarantee that a woman will develop gestational diabetes, but they do increase the chances. Some common risk factors include:


Women over 25 are at a higher risk of developing gestational diabetes. The risk increases further with advancing maternal age.

Obesity or Excess Weight

Women who are overweight or obese before becoming pregnant are more likely to develop gestational diabetes. Body mass index (BMI) plays a role in insulin resistance.

Family History

A family history of diabetes, especially type 2 diabetes, can increase the risk of gestational diabetes. Genetic factors influence how the body processes glucose and insulin.

Ethnic Background

Certain ethnic groups have a higher risk of gestational diabetes, including African, Hispanic, Native American, South Indian and Malays.

Previous Gestational Diabetes

Women who had gestational diabetes during a previous pregnancy are more likely to develop it again in subsequent pregnancies.

Polycystic Ovary Syndrome (PCOS)

Women with PCOS have an increased risk of insulin resistance, which can contribute to the development of gestational diabetes.

History of Large Babies

Women who have previously given birth to a baby weighing more than 9 pounds (4.1 kilograms) are at a higher risk of developing gestational diabetes.

Pre-existing Health Conditions

Conditions such as prediabetes or impaired glucose tolerance, which involve higher-than-normal blood sugar levels, can increase the risk of gestational diabetes.

Physical Inactivity

A sedentary lifestyle and lack of regular physical activity can contribute to insulin resistance and increase the risk of gestational diabetes.

High Blood Pressure

Women with high blood pressure or a history of hypertension are at an increased risk of developing gestational diabetes.

Multiple Pregnancies

Women carrying twins, triplets, or more are at a higher risk due to the increased demand for insulin.

Certain Medications

Some medications, such as corticosteroids, can increase the risk of gestational diabetes.

What Are the Signs of Gestational Diabetes?

Gestational diabetes often doesn’t present with noticeable symptoms, so routine screening during pregnancy is crucial to detect it. However, in some cases, subtle signs or symptoms might indicate the presence of gestational diabetes.
These signs can be similar to those of other types of diabetes or might mimic common pregnancy discomforts. Experiencing these signs doesn’t necessarily mean you have gestational diabetes, but it’s best to consult your doctor if you’re concerned. Some potential signs include:

Increased Thirst and Urination

Feeling unusually thirsty and needing to urinate more frequently than usual can be signs of elevated blood sugar levels. This is a common symptom in other types of diabetes as well.


Feeling more tired than usual, even after getting enough rest, can be associated with changes in blood sugar levels.

Frequent Infections

High blood sugar levels can weaken the immune system, making you more susceptible to infections, particularly urinary tract infections.

Blurred Vision

Fluctuations in blood sugar levels can affect the lens of the eye and cause temporary blurred vision.

Increased Hunger

Elevated blood sugar levels can increase hunger or sudden cravings for sugary or carbohydrate-rich foods.

Unexplained Weight Loss or Gain

Some women might experience weight loss despite increased hunger, while others might gain weight more rapidly than expected during pregnancy.

Nausea and Vomiting

Nausea and vomiting, often called morning sickness, can be exacerbated by high blood sugar levels.

Irritability or Mood Changes

Fluctuations in blood sugar levels can impact mood and lead to irritability or mood swings.

What Medical Tests and Criteria Are Used to Diagnose Gestational Diabetes?

Diagnosing gestational diabetes involves specific medical tests and criteria to determine whether a pregnant woman’s blood sugar levels are within a healthy range. The recommended screening for gestational diabetes is between the 24th and 28th weeks of pregnancy for most pregnant women. The tests commonly used to diagnose gestational diabetes include:

Glucose Tolerance Test (GTT)

  • The woman fasts overnight before the test.
  • Fasting blood sugar level is measured.
  • Then, another sugary solution with a higher concentration of glucose is consumed.
  • Blood sugar levels are tested regularly (usually 1, 2, and sometimes 3 hours after consuming the solution).
  • The results are compared against established criteria for diagnosing gestational diabetes.
The diagnostic criteria for gestational diabetes can vary slightly based on different guidelines and doctors. However, commonly accepted criteria include:
  • Fasting Blood Sugar Level: 92 mg/dL (5.1 mmol/L) or higher
  • One-Hour Blood Sugar Level: 180 mg/dL (10.0 mmol/L) or higher
  • Two-Hour Blood Sugar Level: 153 mg/dL (8.5 mmol/L) or higher
If any of these blood sugar levels are exceeded during the GTT, gestational diabetes is diagnosed.
Routine prenatal care and glucose screening are essential to identify and manage gestational diabetes. Early detection and proper management can help prevent complications for both the mother and the baby.

How Is Gestational Diabetes Treated?

Treating gestational diabetes aims to keep blood sugar levels within a healthy range to ensure the well-being of both the mother and the developing baby. The primary focus is on managing blood sugar levels through lifestyle modifications, but in some cases, medical interventions such as insulin therapy might be necessary. The treatment approach can vary based on individual circumstances, but here are the key components:

Dietary Changes

  • A registered dietitian or doctor will develop a personalised meal plan that helps regulate blood sugar levels.
  • The plan typically includes monitoring carbohydrate intake, distributing meals and snacks throughout the day, and choosing complex carbohydrates with a lower glycemic index.
  • Portion control and balanced meals are emphasised to prevent spikes in blood sugar levels.

Regular Physical Activity

  • Regular, moderate-intensity physical activity can help improve insulin sensitivity and regulate blood sugar levels.
  • Your doctor will guide you on appropriate exercises and activity levels during pregnancy.

Blood Sugar Monitoring

  • Regular monitoring of blood sugar levels, usually using a glucose meter, helps track how different foods, physical activity, and other factors affect blood sugar.
  • Monitoring helps you and your doctor adjust your meal plan and treatment.

Insulin Therapy

  • Insulin therapy might be recommended if blood sugar levels remain consistently elevated despite dietary changes and physical activity.
  • Insulin is usually given through injections; your doctor will guide you on dosage and timing.


  • In some cases, oral medications might be considered to help manage blood sugar levels. However, these are typically not the first-line treatment for gestational diabetes.

What are the possible complications of gestational diabetes?

Being diagnosed with gestational diabetes can be a scary and confusing time. But with good management of blood sugar levels, a healthy pregnancy can be achieved. Monitoring your blood sugar levels and meeting your targets will reduce your risk of complications and increase your chances of having a healthy pregnancy and baby. However, if your gestational diabetes isn’t managed well, it can put you at an increased risk of developing complications.
Continuous high blood sugar levels can lead to:
  • induced labour
  • caesarean section
  • a larger than normal baby, which could make for a more painful birth and possible stress for the baby A large baby can be difficult to deliver through the pelvis (called “shoulder dystocia”). A vaginal delivery increases the risk of injuring a large baby (eg, broken bones or nerve injury). A large baby is also more likely to cause injury to the mother during the delivery (eg, more severe vaginal lacerations)
  • newborn having low blood sugar levels
  • baby having a higher risk of being overweight or obese and developing type 2 diabetes in later life. There is also a small risk of stillborn if sugar level is high. . Gestational diabetes can affect how well the placenta works. If the placenta isn’t working as well as it should, it can make the baby unwell. This can affect their movements.

How do I prevent complications?

This should include how to check your blood sugar levels and target levels, advice about making healthier food choices, the importance of daily physical activity and taking your medication, including insulin, if you need it.

Regular Medical Checkups

  • Regular prenatal appointments with your doctor are crucial to monitor your health and the baby’s growth and development.
  • Your doctor will monitor your blood sugar levels, assess the effectiveness of your treatment plan, and make any necessary adjustments.

Education and Support

  • Education about gestational diabetes, its management, and its potential impact on pregnancy and childbirth is essential.
  • Support from healthcare professionals, such as endocrinologists, dietitians, and diabetes educators, can help you navigate the challenges of managing gestational diabetes.
Gestational diabetes typically resolves after childbirth. However, women with gestational diabetes are at an increased risk of developing type 2 diabetes later in life. After giving birth, it’s recommended to undergo postpartum glucose testing and maintain a healthy lifestyle to reduce the risk of developing type 2 diabetes.
Your doctor will tailor the treatment plan to your needs and closely monitor your progress throughout the pregnancy. Consistently managing blood sugar levels can help ensure a safe and healthy pregnancy for you and your baby.

Dr. Cho Li Wei 朱丽薇医生

Consultant Endocrinologist
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