Decoding Gestational Diabetes Mellitus Guide

Decoding Gestational Diabetes Mellitus Guide

The Ultimate Guide to Gestational Diabetes Mellitus

Get Doctor-Approved Answers and Finally Understand Gestational Diabetes, Five Minute Read

Written by Cristina Sciarra. Medically reviewed by Rachael Sullivan, DO, FACOOG.


Table Of Contents:


If you’re a busy mom who was recently diagnosed with Gestational Diabetes Mellitus (GDM), you probably have lots of questions and not much time to research.  

In this comprehensive guide, you’ll find clear, concise answers to help you easily understand gestational diabetes, whether you are a pregnant person yourself, or are the friend or loved one of someone experiencing gestational diabetes. You’ll discover the information you need to understand this diagnosis, and the steps you can take to keep you and your baby healthy. 

So get ready! We’re going to explore:

  • Causes
  • Symptoms
  • Diagnosis
  • Treatment
  • Management

I’ll also share helpful resources to answer more of your pressing questions, and I’ll explain how to find healthy and delicious recipes to take the pain out of meal planning.

Let's get started!

What is Diabetes?

what is diabetes?

Most basically, diabetes affects how your body transforms food into energy.

Your body breaks down the food you eat into sugar, or glucose, which is then released into your bloodstream. 

When your blood sugar elevates, your pancreas is signaled to release insulin, which acts like a key, opening the door to allow blood sugar into cells, to be used as energy.  

When you have diabetes, your body either doesn’t make enough insulin, or cannot use insulin as efficiently as it should. Without sufficient insulin, excess blood sugar remains in the bloodstream. Over time, this can cause serious health problems.

What is Gestational Diabetes?

Gestational diabetes mellitus (GDM) is type of diabetes that occurs during pregnancy when your hormones make it difficult for the body to use insulin effectively. When the body cannot produce enough insulin or use it effectively, it leads to high blood sugar levels. High blood sugar levels can cause complications for both the mother and the baby.

True gestational diabetes goes away as soon as the placenta is delivered. 

visual explanation of gestational diabetes

The exact cause of gestational diabetes is still unknown. While there are risk factors, it is possible for any birthing person to develop gestational diabetes. It is also important to remember: a gestational diabetes diagnosis is not your fault! You cannot control how the hormones in your placenta operate. 

While uncontrolled gestational diabetes can cause serious health risks, it is possible to treat and manage. 

Up to 20% of pregnancies are impacted by this health condition. Dealing with gestational diabetes can be very frustrating, but you are not alone.

some women feel shame over a gestational diabetes diagnosis

What Happens if Gestational Diabetes Mellitus is Left Untreated, Short-Term?

Untreated gestational diabetes mellitus can cause complications for both the mother and the baby.

For Mom: Short-term Complications Include:

For baby: Short-term Complications Include:

untreated gestational diabetes can be dangerous for mother and baby

What Happens if Gestational Diabetes Mellitus is Left Untreated, Long-Term?

For Mom: Long-term Complications Include:

  • A higher risk for developing type-2 diabetes later in life (source)

For Baby: Long-term Complications Include:

  • A higher risk for obesity later in life (source)
  • A higher risk for type-2 diabetes later in life (source)

What are the Symptoms of Gestational Diabetes Mellitus?

Here’s the problem. Gestational diabetes mellitus typically has no symptoms (or if women do experience symptoms, they are very mild.) 

gestational diabetes typically has no symptoms

But it’s always a good idea to tell your healthcare provider if you are experiencing any of the following conditions:

  • Frequent urination
  • Increased thirst
  • Fatigue
  • Blurred vision
  • Nausea and vomiting

Note: these symptoms are not specific to gestational diabetes and can be attributed to other pregnancy-related conditions, or just being pregnant in general. 

The best choice is to get tested for gestational diabetes mellitus during each of your pregnancies.

When is Gestational Diabetes Mellitus Tested for and Diagnosed?

Gestational diabetes mellitus is usually tested for and diagnosed between the 24th and 28th week of pregnancy. 

Some women may be tested earlier, if they are especially high risk, or if they've had a past GDM pregnancy. 

gestational diabetes is typically tested for between weeks 24 and 28 of pregnancy

How is Gestational Diabetes Diagnosed?

First, your healthcare provider will give you a glucose challenge test (also known as the one-hour glucose tolerance test). 

You don't need to fast before taking this test. In your doctor's office, you will drink a sugary solution. One hour later, your blood sugar level will be measured. 

glucose challenge test

Results of the glucose challenge test are given in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L), depending where in the world you are.

  • A blood sugar level below 140 mg/dL (7.8 mmol/L) is considered standard.
  • A blood sugar level of 140 mg/dL (7.8 mmol/L) to less than 190 mg/dL (10.6 mmol/L) indicates the need for a three-hour glucose tolerance test to diagnose gestational diabetes.
  • A blood sugar level of 190 (10.6 mmol/L) or higher indicates gestational diabetes. Further testing might not be needed.

If the test results are outside the standard range, your healthcare provider will call you in for an oral glucose tolerance test (OGTT). 

oral glucose tolerance test (OGTT)

For this test, you cannot eat or drink for eight hours beforehand. (So it's good to schedule this test first thing in the morning.) 

When you arrive at your healthcare provider's office, a sample of blood will be taken. This will be used to measure your fasting blood glucose level. Then, you will drink another glucose solution. Your blood glucose level will be tested again one, two and three hours after you drink the solution.

For the three-hour test:

  • A normal fasting blood glucose level is lower than 95 mg/dL (5.3 mmol/L).
  • One hour after drinking the glucose solution, a normal blood glucose level is lower than 180 mg/dL (10 mmol/L).
  • Two hours after drinking the glucose solution, a normal blood glucose level is lower than 155 mg/dL (8.6 mmol/L).
  • Three hours after drinking the glucose solution, a normal blood glucose level is lower than 140 mg/dL (7.8 mmol/L).

If two or more of your blood sugar levels are higher than normal, you will be diagnosed with gestational diabetes.

How is Gestational Diabetes Mellitus Treated?

normal pregnancy glucose levels

When tackling gestational diabetes mellitus, the goal is to keep your blood sugar levels stable and within a normal range as much as possible. 

The American Diabetes Association recommends your (pregnancy) blood glucose levels be:

  • Fasting: lower than 90 mg/dL (5 mmol/L) or less
  • One hour after eating: 140 mg/dL (7.8 mmol/L) or less
  • Two hours after eating: 120 mg/dL (6.7 mmol/L) or less

Gestational diabetes is managed through a combination of diet and exercise, and—sometimes—medication.

Monitoring and Tracking Blood Sugar Levels

Monitoring and tracking your blood sugar levels is an important part of managing gestational diabetes. 

Your healthcare provider may ask you to check your blood sugar level several times a day using a glucose meter. You will be asked to record your blood sugar levels, and then send in the results for weekly review. 

Your healthcare provider may also send you for non-stress tests and extra scans.

it is important to track your blood glucose numbers when you have gestational diabetes

The Winning Combo: Diet and Exercise (and Maybe Medication)

If you’re wondering what’s the best way to keep your blood sugar levels in the proper range, the answer is through a combination of diet and exercise and—sometimes—medication.

Your healthcare provider may offer nutrition counseling in-office, or suggest you visit an outside dietician or nutritionist. I recommend you seek help from someone who has specific knowledge about GDM. Eating for gestational diabetes often requires a stricter diet than type 2 diabetes.

In fact, gestational diabetes is different for everyone: some people can eat a diet only slightly modified from what they'd normally eat, whereas other people will need to make major adjustments. 

Exercise is important as well. Work with your doctor to determine the level of activity that’s safe for you and your baby throughout your pregnancy. (And that you feel is manageable for you!) 

Gestational diabetes is also not static: often, your diet will need to become stricter the further your pregnancy progresses. 

every woman responds differently to gestational diabetes

It is important to remember a few things:

  • Try not to compare: every pregnancy is different! 
  • You may be able to eat certain foods in the afternoon, but not in the morning. And a food that worked well for your blood sugar levels one day may spike you the next. This is the nature of gestational diabetes. Try not to get too frustrated by these fluctuations. 
  • Remember that no one is perfect: it will be ok if you have occasional spikes. The goal is to keep your numbers within range as much as possible.

If your numbers cannot be regulated by diet and exercise alone, your doctor may prescribe medication as an additional tool. 

Always remember that this is treatable—and working with your health care team can help ensure a healthy pregnancy.

The Role of Food in Gestational Diabetes Treatment

Let’s talk more about nutrition. Diet is an essential part of managing gestational diabetes. You should aim to eat a balanced, nutrient-dense diet, high in fiber and protein, and low in sugar and simple carbohydrates.

The American Diabetes Association recommends consuming a variety of nutrient-dense foods such as whole grains, lean proteins, fruits, vegetables, and healthy fats. It's essential to monitor carbohydrate intake since it directly impacts blood glucose levels. 

Some tips for eating a healthy GDM diet include:

  • Focus on eating: lean proteins, non-starchy vegetables, and healthy fats.
  • Focus on eating complex carbohydrates, while avoiding simple carbohydrates. 
  • Distribute carbohydrates consumption throughout the day.
  • Eat small, frequent meals throughout the day.
  • Avoiding sugary drinks and snacks, added sugars, and most fruit. 
  • Strictly limit sweets and desserts.
  • Drink lots of water.

Your healthcare provider may also refer you to a registered dietitian or nutritionist, who can help you learn which foods will both meet your nutritional needs, and help keep your blood sugar level within a normal range.

tips for eating on a gestational diabetes diet

A balanced diet is crucial for maintaining adequate glucose levels during pregnancy. 

The Role of Exercise in Gestational Diabetes Treatment

Exercise is another important tool in managing gestational diabetes. Exercise can help lower blood sugar levels, and improve insulin sensitivity. 

Regular physical activity also reduces the risk of other pregnancy-related complications, from constipation to cesarean section and preeclampsia.

Some tips for exercising during pregnancy include:

  • Getting at least 30 minutes of moderate-intensity exercise most days of the week.
  • Choosing low-impact exercises such as walking, swimming, or cycling.
  • Choosing muscle-strengthening exercises like yoga or pilates. 
  • Avoiding exercises that involve lying on your back or jumping.
  • Checking your blood sugar level before and after exercise.

Your healthcare provider may also refer you to a physical therapist or trainer to develop an exercise plan. 

aim to exercise 150 minutes per week when pregnant

Will I Need to Take Medication for Gestational Diabetes Mellitus?

Maybe. If diet and exercise alone are not able to keep your blood sugar levels within a normal range, your healthcare provider may prescribe medication. 

The most common medication used to treat gestational diabetes is insulin. Insulin is naturally occuring in the body, and does not cross the placenta. If you are prescribed insulin, you will need to inject it yourself. 

The other two most common forms of gestational diabetes medications are metformin and glyburide.

Remember: A Gestational Diabetes Diagnosis is Not Your Fault

I too had GD and I remember how scary it can feel to receive a gestational diabetes diagnosis. But don’t blame yourself. You cannot control how the hormones in your placenta operate.

gestational diabetes is not your fault

If It’s Not My Fault, What Did Cause it? Are there Risk Factors?

Unfortunately the medical community doesn’t know the exact cause. Anyone can develop gestational diabetes, although some women are at a higher risk than others.

gestational diabetes risk factors

Cited risk factors include:

  • Family history 
  • Genetics 
  • Polycystic ovary syndrome (PCOS)
  • Being non-Caucasian
  • Gestational age (being over the age of 25)
  • A previously large baby 
  • High blood pressure
  • High percentage of fatty tissue

Having some (or all) of these risk factors is not guarantee that you will develop gestational diabetes! (Just as having none of these risk factors does not guarantee a GDM-free pregnancy.)

Coping with Gestational Diabetes Emotionally

It is totally normal to feel frustrated, angry, scared, and overwhelmed by a gestational diabetes diagnosis. Many women also feel shame, although they should not.

It's important to take care of your mental and emotional health during pregnancy. 

it is important for your partner to understand and support you when you have gestational diabetes

Some tips for coping with gestational diabetes emotionally include:

  • Talking to your healthcare provider about your concerns.
  • Talking to your friends and family about how they can support you. 
  • Joining a support group for women with gestational diabetes.
  • Practicing relaxation techniques such as deep breathing or meditation.
  • Seeking professional help if you are feeling overwhelmed or anxious.
  • Remembering that, although this is difficult, gestational diabetes does not last forever

Coping with the emotional challenges of GDM should involve the support of loved ones as well as healthcare professionals. 

Having a partner really understand and respect your new diet limitations can be very helpful. 

Ask those closest to you to respect your new dietary limitations, and to participate in making it easier for you to enjoy meals and social gatherings. 

ask your friends and family to respect your diet when you have gestational diabetes

What Happens After I Deliver? Postpartum Care After GDM Diagnosis

Usually around six to twelve weeks after you deliver, you’ll have a follow-up assessment with your doctor.

This evaluation may include an oral glucose tolerance test, to determine if you have prediabetes or type 2 diabetes. 

Proper postpartum care is essential for managing the long-term risks associated with GDM, such as developing type 2 diabetes later in life. 

A balanced diet and regular exercise can help mitigate these long-term risks. 

proper postpartum care is essential for managing the long-term risks of GDM


We hope this guide has helped you better understand the causes, symptoms, diagnosis, treatment, and prevention of gestational diabetes. Whether you are a pregnant woman, a concerned family member or friend, this guide was designed to arm you with the knowledge and tools necessary to manage gestational diabetes and ensure a happy and healthy pregnancy.

Managing GDM efficiently necessitates a blend of dietary adjustments, movement, and (sometimes) medication. By addressing these factors, pregnant women diagnosed with GDM can reduce the complications associated with this condition.

Remember most women with well-managed gestational diabetes have healthy pregnancies and deliver healthy babies. 


Where Can I Get More Support?

GD Kitchen! I created this resource to solve a problem that I wish someone had already solved before my pregnancy. And I've teamed up with OB Rachael Sullivan, DO and nutritionist Jamie Askey, RN, so that you will have all the resources, and all the confidence, I wish I’d had. 

If you need immediate help finding recipes that are designed for women on a GD nutrition plan, try our six free gestational diabetes recipes here. I personally spent hours in the kitchen developing each one. They’re great for the entire family. 

I created the Recipe Membership to solve eating happily, easily, and deliciously on a GDM diet. 


What's inside? Thoroughly-tested recipes, written by a recipe developer, and reviewed by an RN Nutritionist + Menus to make meal planning easy and fun + Informational and Worksheet Resources + Seasonal Newsletters + Product Suggestions to make your life with GDM easier and more delicious 


Does all of this sound a bit overwhelming? Check out the Gestational Diabetes Basics 101 Guide.

What's inside? A thirty-minute narrated informational presentation + four, "cheat sheet" worksheets you can reference any time: 1. You've Been Diagnosed With Gestational Diabetes, Now What?! 2. How Gestational Diabetes Affects Your Body 3. Blood Glucose Number Primer 4. The Difference Between Types of Diabetes


If the idea of figuring out how to continually monitor your glucose levels daily seems overwhelming, you can grab my Glucose Meter + Diaries bundle here!

What's inside? A fifteen-minute narrated informational presentation + A video demonstration of how exactly to use you meter + Digital and Printable Made-For-You Templates, removing the guesswork and confusion out of food and blood glucose logs 

Do you know someone who has been diagnosed with gestational diabetes mellitus? Purchase a gift card they can use at GD Kitchen. Give the gift of support! 


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