Your Guide to Gestational Diabetes During Pregnancy

Gestational diabetes is a type of diabetes that develops during pregnancy. This guide from Param Maternity & Surgical Nursing Home explains what it is, who is at risk, how it's diagnosed, and how to manage it for a healthy pregnancy and baby.

Published: October 27, 2023•Updated: October 27, 2023

Understanding Gestational Diabetes: A Guide for Expectant Mothers

Welcome to your guide on Gestational Diabetes Mellitus (GDM). Receiving a diagnosis of gestational diabetes can bring many questions and concerns, but please know that with proper care and management, you can have a healthy pregnancy and a healthy baby. This guide from Param Maternity & Surgical Nursing Home is here to help you understand what GDM is, why it happens, and how we can work together to manage it effectively.

What is Gestational Diabetes?

Gestational diabetes mellitus (GDM) is a type of diabetes that develops or is first recognized during pregnancy. It means your blood sugar levels are higher than normal, but it doesn't mean you had diabetes before pregnancy. This condition can occur even if you've never had diabetes before and typically resolves after your baby is born. It's important to manage GDM because it can affect both your health and your baby's health.

You might also hear it simply called "Gestational Diabetes."

Why Does Gestational Diabetes Happen?

During pregnancy, your body goes through many changes to support your growing baby. One of these changes involves hormones produced by the placenta. These hormones are vital for your baby's development, but they can also make your body less responsive to insulin, a hormone that helps control blood sugar. This is called "insulin resistance."

Normally, your pancreas (an organ that makes insulin) would produce extra insulin to overcome this resistance. However, if your pancreas can't produce enough insulin to keep up with the increased demand, your blood sugar levels rise, leading to gestational diabetes.

Who is at Risk for Gestational Diabetes?

While any pregnant woman can develop GDM, some factors can increase your risk. It's important to remember that having risk factors doesn't mean you will definitely get GDM, and not having them doesn't mean you won't.

Factors You Cannot Change (Non-Modifiable):

Age: Being over 25 years old (some guidelines suggest over 30 or 40).
Previous GDM: If you had gestational diabetes in a past pregnancy.
Family History: Having a close family member (like a parent or sibling) with diabetes.
Previous Large Baby: Delivering a baby weighing more than 9 pounds (about 4 kg) in a previous pregnancy.
Ethnicity: Being of South Asian, Black Caribbean, Hispanic, Native American, or Pacific Islander descent.
Polycystic Ovary Syndrome (PCOS): A hormonal condition.
Unexplained Pregnancy Loss: A history of unexplained stillbirth or birth of a baby with birth defects.

Factors You Can Influence (Modifiable):

Weight: Being overweight or obese before pregnancy (BMI ≥25 kg/m² or ≥30 kg/m²).
Physical Activity: Not being physically active.
Diet: Eating patterns high in saturated fat and low in fiber.

Protective Factors:

Being physically active before pregnancy.
Following healthy dietary patterns (like a Mediterranean diet).
Having a normal weight before pregnancy.

Symptoms of Gestational Diabetes

One of the most important things to know about gestational diabetes is that it often has no noticeable symptoms. This is why screening is so important during pregnancy.

If symptoms do occur, they are usually mild and can easily be mistaken for normal pregnancy discomforts. These might include:

Increased thirst (polydipsia)
More frequent urination (polyuria)
Increased hunger (polyphagia)
Blurred vision
Feeling unusually tired
Nausea

When to Seek Immediate Medical Attention (Red Flag Symptoms):

While GDM itself rarely causes emergency symptoms, its complications can. Please contact your healthcare provider immediately if you experience any of the following, as they could be signs of a serious condition like preeclampsia:

A severe headache that doesn't go away.
Changes in your vision, such as blurriness, seeing flashing lights, or spots.
Severe pain just below your ribs.
Sudden and rapid swelling in your face, hands, or feet.

Symptoms of very high blood sugar (diabetic ketoacidosis), though extremely rare in GDM, are also a medical emergency.

How is Gestational Diabetes Diagnosed?

Gestational diabetes is typically diagnosed through specific blood tests performed during your pregnancy. Most women are screened between 24 and 28 weeks of gestation. If you have certain risk factors, your doctor might recommend earlier screening in the first trimester.

There are different approaches to screening and diagnosis around the world, but the goal is always to identify GDM to ensure the best care for you and your baby.

Common Diagnostic Tests:

Glucose Challenge Test (GCT): This is often the first step. You'll drink a sugary liquid, and your blood sugar will be checked one hour later. You usually don't need to fast for this test. If your blood sugar is above a certain level, it suggests you might have GDM, and a follow-up test is needed.
Oral Glucose Tolerance Test (OGTT): If your GCT is positive, or if your doctor opts for a one-step diagnostic approach, you'll have an OGTT. This test requires you to fast overnight. Your blood will be drawn to check your fasting blood sugar. Then, you'll drink a more concentrated sugary liquid, and your blood sugar will be checked at specific intervals (e.g., 1 hour, 2 hours, or 3 hours) afterward.

Your doctor will interpret the results based on established guidelines to determine if you have gestational diabetes. It's important to complete these tests as recommended, even if you feel well, because GDM often has no symptoms.

Managing Gestational Diabetes

The good news is that gestational diabetes can be effectively managed to ensure a healthy pregnancy and baby. Your healthcare team will work closely with you to create a personalized management plan.

1. Lifestyle Management (The First Step):

Medical Nutrition Therapy (MNT): This is the cornerstone of GDM management. You'll likely meet with a registered dietitian who will help you understand how different foods affect your blood sugar. They'll guide you in creating a meal plan that balances carbohydrates, proteins, and healthy fats, ensuring you get adequate nutrition for your pregnancy while keeping blood sugar levels stable. This isn't about "dieting" but about making healthy food choices.
Physical Activity: Regular, moderate-intensity exercise is highly beneficial, unless your doctor advises against it. Aim for at least 30 minutes of aerobic activity on most days of the week. Walking, swimming, or prenatal yoga are great options. Exercise helps your body use insulin more effectively and lowers blood sugar.
Blood Glucose Monitoring: You'll learn how to check your blood sugar levels at home using a small device called a glucometer. This usually involves checking your blood sugar four times a day: first thing in the morning (fasting) and then 1 or 2 hours after each main meal. This monitoring helps you and your healthcare team understand how your body is responding to food and activity, and whether your treatment plan needs adjustments.

2. Glycemic Targets (What We Aim For):

Your healthcare team will set specific blood sugar targets for you to aim for. While exact numbers can vary slightly between guidelines, common targets include:

Fasting: Equal to or less than 95 mg/dL (5.3 mmol/L)
1-hour after meals: Equal to or less than 140 mg/dL (7.8 mmol/L)
2-hours after meals: Equal to or less than 120 mg/dL (6.7 mmol/L)

Your doctor will discuss your individual targets with you.

3. Medical Treatment (If Lifestyle Isn't Enough):

If lifestyle changes alone aren't enough to keep your blood sugar levels within target, your doctor may recommend medication. This usually happens after 1-2 weeks of consistent lifestyle management.

Insulin: Insulin injections are often the preferred first-line medication for GDM because insulin does not cross the placenta to your baby in significant amounts. Your doctor will teach you how to administer insulin, and the dosage will be adjusted based on your blood sugar readings.
Oral Medications:
- Metformin: This medication is commonly used and helps your body use insulin more effectively. It does cross the placenta, but long-term safety data for babies are generally reassuring, though still being studied. Some studies suggest it might be associated with lower maternal weight gain.
- Glyburide (Glibenclamide): The use of this medication has declined. It also crosses the placenta and has been associated with a higher risk of low blood sugar in newborns and larger babies compared to insulin or metformin.

Follow-up and Monitoring:

You'll have regular antenatal visits to monitor your health and your baby's growth. This may include additional ultrasounds to check your baby's size and well-being, especially if your GDM is difficult to control or requires insulin.

Referrals to a registered dietitian or a diabetes educator are common and highly beneficial. In complex cases, you might also be referred to a Maternal-Fetal Medicine (MFM) specialist.

Potential Complications of Gestational Diabetes

Uncontrolled gestational diabetes can lead to complications for both you and your baby. This is why careful management is so important.

For the Mother (During Pregnancy):

Preeclampsia: A serious condition characterized by high blood pressure and signs of organ damage.
Higher Chance of C-section: Due to a larger baby or other complications.
Birth Trauma: Increased risk of injuries during delivery, such as perineal tears, especially if the baby is large.
Polyhydramnios: Too much amniotic fluid around the baby.

For the Mother (Long-Term):

Type 2 Diabetes: A significantly increased risk of developing type 2 diabetes later in life, with about 50% of women developing it within 10-20 years.
Metabolic Syndrome and Heart Disease: Increased risk of these conditions.

For the Baby (During Pregnancy and After Birth):

Macrosomia: The baby growing too large (over 9 pounds or 4 kg), which can lead to difficult delivery.
Shoulder Dystocia: A serious complication where the baby's shoulder gets stuck during delivery.
Birth Injuries: Such as nerve damage or bone fractures, often related to a large baby and difficult delivery.
Neonatal Hypoglycemia: Low blood sugar in the newborn shortly after birth, requiring close monitoring and sometimes treatment.
Neonatal Jaundice: Yellowing of the skin and eyes in the newborn.
Respiratory Distress Syndrome: Breathing problems in the newborn.
Increased Risk of Perinatal Mortality: Though rare, the risk is elevated, especially with poorly controlled GDM.

For the Baby (Long-Term):

Increased risk of childhood obesity.
Increased risk of developing impaired glucose tolerance and type 2 diabetes later in life.

Preventing Gestational Diabetes and Its Effects

While not all cases of GDM can be prevented, especially if you have strong risk factors, there are important steps you can take:

Before Pregnancy (Primary Prevention):

Healthy Lifestyle: Aim for a healthy diet and regular physical activity before you become pregnant.
Weight Management: Achieving a healthy body weight before conception is one of the most effective ways to reduce your risk.

During Pregnancy (Secondary Prevention):

Early Screening: Participating in recommended GDM screening helps identify the condition early.
Strict Glycemic Control: Once diagnosed, diligently managing your blood sugar levels through diet, exercise, and medication (if needed) is crucial to prevent complications for you and your baby.

What Happens After Delivery? (Prognosis)

For most women, blood sugar levels return to normal very quickly after the baby is born, usually within hours or days. This is because the placenta, which produces the hormones causing insulin resistance, is delivered.

Risk of Recurrence:

If you've had GDM in one pregnancy, your risk of developing it again in future pregnancies is high (ranging from 30% to 70%).

Long-Term Health:

Having gestational diabetes significantly increases your lifetime risk of developing type 2 diabetes. This risk is highest in the first 5-10 years after delivery. You also have an increased risk for high blood pressure and heart disease.

Postpartum Screening:

Because of these long-term risks, it's crucial to be screened for diabetes after your baby is born. Your doctor will recommend a blood test (usually a 75-g, 2-hour OGTT) between 4 and 12 weeks postpartum to check if your blood sugar levels have returned to normal or if you have developed prediabetes or type 2 diabetes.

Even if your postpartum screen is normal, you should continue to be re-screened for diabetes at least every 1 to 3 years, as recommended by your doctor.

Frequently Asked Questions About Gestational Diabetes

Important Note:

This guide provides general information and is not a substitute for professional medical advice. Always consult with your healthcare provider for diagnosis, treatment, and any questions regarding your specific medical condition.

Frequently Asked Questions

What is the difference between gestational diabetes and type 2 diabetes?

Gestational diabetes (GDM) develops during pregnancy and usually resolves after birth. Type 2 diabetes is a chronic condition that can develop at any age and is permanent. While GDM increases your risk for Type 2 diabetes later, they are distinct conditions.

Will I need to take insulin injections?

Not necessarily. The first step in managing GDM is lifestyle changes (diet and exercise). If these are not enough to keep your blood sugar levels within target, your doctor may recommend medication. Insulin is often the preferred first-line medication because it does not significantly cross the placenta.

What are the target blood sugar levels I should aim for?

Common targets are: Fasting: ≤95 mg/dL (5.3 mmol/L); 1-hour post-meal: ≤140 mg/dL (7.8 mmol/L); 2-hours post-meal: ≤120 mg/dL (6.7 mmol/L). Your doctor will provide your specific targets.

How many times a day do I need to check my blood sugar?

Typically, you will need to check your blood sugar four times a day: once in the morning before eating (fasting) and then 1 or 2 hours after each main meal. Your healthcare team will give you specific instructions.

What specific foods should I limit or avoid?

You will work with a registered dietitian to create an individualized meal plan. The focus is on balancing carbohydrates, choosing healthy fats, and ensuring adequate nutrition. This often involves limiting sugary drinks, processed foods, and being mindful of carbohydrate portions.

Can I still have a vaginal delivery?

Many women with GDM can have a vaginal delivery. However, if your baby grows very large (macrosomia) due to uncontrolled GDM, or if other complications arise, your doctor might recommend a Cesarean delivery. Your healthcare team will discuss the safest delivery plan for you and your baby.

Will my baby be born with diabetes?

No, your baby will not be born with diabetes. However, babies born to mothers with GDM have an increased risk of certain issues shortly after birth, such as low blood sugar (neonatal hypoglycemia) and jaundice. They also have a higher long-term risk of obesity and developing type 2 diabetes later in life.

Is gestational diabetes a permanent condition?

For the vast majority of women, gestational diabetes resolves almost immediately after delivery of the placenta. However, having GDM significantly increases your risk of developing type 2 diabetes later in life.

What is my personal risk of developing type 2 diabetes later in life?

Women with a history of GDM have a substantially increased lifetime risk of developing type 2 diabetes, with estimates suggesting up to a 7-fold increased risk, and approximately 50% developing it within 10-20 years after pregnancy. Your individual risk depends on various factors, including your lifestyle and other risk factors.

How will GDM affect my baby's growth and weight?

If GDM is not well-controlled, your baby may grow larger than average (macrosomia). This can increase the risk of complications during delivery, such as shoulder dystocia and birth injuries. Your healthcare team will monitor your baby's growth with ultrasounds.

Is it safe for me to continue exercising during pregnancy?

Yes, in most cases, moderate-intensity aerobic exercise is highly recommended and safe during pregnancy, unless your doctor advises against it due to other medical conditions. Aim for at least 30 minutes on most days of the week. Exercise helps manage blood sugar levels.

What are the risks and benefits of taking metformin instead of insulin?

Metformin is an oral medication that helps your body use insulin more effectively. Benefits can include lower maternal weight gain. However, it does cross the placenta, and while long-term safety data for offspring are generally reassuring, they are still limited. Insulin is often preferred as it does not cross the placenta significantly. Your doctor will discuss which medication is best for your specific situation.

Why do I need more frequent ultrasounds than someone without GDM?

More frequent ultrasounds are often recommended to monitor your baby's growth and well-being, especially to check for macrosomia (a baby growing too large) and to assess the amount of amniotic fluid. This helps your healthcare team plan for the safest delivery.

What are the signs of my blood sugar being too high (hyperglycemia)?

GDM is often asymptomatic, so high blood sugar might not have obvious signs. When symptoms do occur, they can include increased thirst, frequent urination, increased hunger, blurred vision, and fatigue. These are often non-specific and can be mistaken for normal pregnancy symptoms.

What are the signs of my blood sugar being too low (hypoglycemia)?

The dossier does not specifically detail symptoms of low blood sugar (hypoglycemia) for the mother with GDM. However, if you are on insulin or certain oral medications, hypoglycemia can be a risk. Your healthcare team will educate you on recognizing and managing low blood sugar symptoms, which commonly include shakiness, sweating, dizziness, confusion, and a rapid heartbeat.

Do I need to see a high-risk pregnancy specialist (MFM)?

Referral to a Maternal-Fetal Medicine (MFM) specialist may be recommended for complex cases, if your blood sugar is difficult to control, or if there are suspected fetal complications. Your primary healthcare provider will guide this decision.

When should I be screened for GDM in my next pregnancy?

If you've had GDM before, your risk of recurrence is high. Your doctor may recommend early screening in the first trimester of your next pregnancy, in addition to the standard screening between 24 and 28 weeks.

What does the oral glucose tolerance test (OGTT) involve?

The OGTT typically involves fasting overnight. Your blood is drawn for a fasting blood sugar level. Then, you drink a specific amount of a sugary liquid. Your blood sugar levels are then checked again at specific intervals (e.g., 1 hour, 2 hours, or 3 hours) after drinking the solution.

Could I have prevented this from happening?

While not all cases of GDM can be prevented, especially if you have strong risk factors you cannot change, maintaining a healthy lifestyle before pregnancy (including a healthy diet and regular physical activity) and achieving a healthy weight before conception are the most effective ways to reduce your risk. Once diagnosed, managing your blood sugar diligently helps prevent complications.

What specific tests will I need after my baby is born?

You will need to be screened for persistent diabetes or prediabetes at 4–12 weeks postpartum, usually with a 75-g, 2-hour Oral Glucose Tolerance Test (OGTT). If this test is normal, you should be re-screened for diabetes at least every 1–3 years.

Will I need to be induced early?

The dossier does not explicitly state early induction as a universal outcome for GDM. However, if GDM is poorly controlled or if there are concerns about fetal complications like macrosomia, your healthcare provider might discuss induction or other delivery timing considerations. This is a decision made based on your individual circumstances.

How does GDM affect my breastfeeding options?

The dossier does not directly address breastfeeding options. However, generally, breastfeeding is encouraged for mothers with GDM as it can have benefits for both mother and baby, including potentially reducing the mother's risk of developing type 2 diabetes later. You should discuss this with your healthcare provider.

What is the difference between a 1-hour and 3-hour glucose test?

The 1-hour glucose test (Glucose Challenge Test or GCT) is typically a screening test, where you drink a 50-g sugary solution and your blood sugar is checked after one hour. It doesn't require fasting. If this test is positive, a 3-hour Oral Glucose Tolerance Test (OGTT) is often performed. The 3-hour OGTT is a diagnostic test, requires fasting, and involves drinking a 100-g sugary solution, with blood sugar checks at fasting, 1 hour, 2 hours, and 3 hours. Some guidelines use a 75-g, 2-hour OGTT as a one-step diagnostic test. Your doctor will explain which test is being used for you.