Maternity - Pregnancy, part 10: Complications: Gestational Diabetes Mellitus

by Meris Shuwarger BSN, RN, CEN, TCRN September 13, 2021 Updated: August 09, 2023 4 min read

In this article, we discuss gestational diabetes mellitus (GDM), a complication that can occur during pregnancy.

This series follows along with our Maternity Nursing Flashcards, which are intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI, and NCLEX.

Cool Chicken When you see this Cool Chicken, that indicates one of Cathy's silly mnemonics to help you remember. The Cool Chicken hints in these articles are just a taste of what's available across our Level Up RN Flashcards for nursing students!

What is gestational diabetes mellitus (GDM)?

Gestational diabetes (GDM) is diabetes that occurs during pregnancy in someone who is not diabetic. A patient with gestational diabetes will have impaired glucose tolerance during their pregnancy.

Risk factors for GDM

The risk factors for GDM parallel those for diabetes mellitus and include obesity, hypertension (HTN), having a family history of diabetes mellitus, or having had gestational diabetes mellitus during a previous pregnancy.

Signs and symptoms of GDM

A patient with gestational diabetes is usually asymptomatic, which is why it’s important to screen for this condition. If the patient does display signs or symptoms, these will be the same as for a person with diabetes, and include polyuria and polydipsia — excessive urination and excessive thirst — which are the most common. Remember, however, that pregnancy will cause a patient to urinate more frequently than normal to begin with, which makes polyuria hard to distinguish as a diabetes-specific symptom.

Labs and diagnostics for GDM

Patients experiencing pregnancy will be screened for GDM via an oral glucose tolerance test, or OGTT. This test takes one hour to be performed. Patients who fail the one-hour test will take a three-hour version of the test, which will diagnose gestational diabetes.

You can learn more about diabetes screening, labs, and more with our Lab Values Study Guide & Flashcard Index, a list of lab values covered in our Lab Values Flashcards for nursing students.

Treatment for GDM

Treatment for GDM, as with diabetes, will require the patient to undergo lifestyle modifications, which may include increasing the amount of exercise they get and changing their diet to include fewer carbs.

Patients should be taught how to monitor their blood glucose. In some cases, insulin may be required. Note that most oral diabetic medications are contraindicated during pregnancy.

Complications of GDM

Among the complications of GDM is fetal macrosomia — “macro” meaning large and “soma” meaning body — that is, a large-sized newborn. If the patient gave birth to a very large baby, that may indicate that the patient had undiagnosed gestational diabetes.

Another serious complication is that the baby is at risk for neonatal hypoglycemia. If the mother had elevated blood sugars while pregnant (even if it’s controlled with lifestyle modifications or medicines), there may still be an impairment of their glucose tolerance, as a lot of that sugar will be passed on to the baby. Once the baby is born and no longer gets all that sugar, the baby's blood sugar will crash. A baby that is macrosomic (that has a large body size) is therefore at risk for hypoglycemia.

Further complications for a patient with gestational diabetes include pre-eclampsia (birth trauma), requiring a c-section (in order to deliver a large baby), and the possibility that they continue to experience diabetes following their pregnancy.

Patient teaching for GDM

If a patient has gestational diabetes, they need to be monitored in the postpartum period to make sure that they return to their baseline. Note that they are still at higher risk for developing diabetes mellitus after pregnancy, which means they need to have a repeat oral glucose tolerance test once they are no longer pregnant to make sure that they return to their baseline.

Learn more about diabetic medications and more with our Pharmacology Second Edition Flashcards.

Hypoglycemia and Hyperglycemia

A patient with gestational diabetes will have similar signs and symptoms of hypoglycemia and hyperglycemia (diabetic ketoacidosis (DKA)) as a patient with diabetes.


Hypoglycemia is low blood sugar.

Signs and symptoms of hypoglycemia

A patient who is hypoglycemic will have a characteristic look. They will be diaphoretic (sweat profusely) and their skin will be cold and clammy. A patient with hypoglycemia may have a headache or shakiness, they could have blurred vision, and they may suffer from hunger.

Treatment for hypoglycemia

Cool Chicken Skin — cold and clammy, need some candy!

A hypoglycemic patient needs to be treated with sugar (hence the Cool Chicken mnemonic). 15 grams of a quickly absorbed carbohydrate, for example a 4 – 6 oz juice or 8 oz milk, (something that has that glucose in it) should be administered, followed by some form of protein intake. Protein is important, because if the treatment only replaces the glucose, the patient will crash again. Protein is a sustained energy source, so the patient is less likely to crash.


Hyperglycemia means the patient's blood sugar is too high.

Signs and symptoms of hyperglycemia

Hallmark signs for hyperglycemia are the three Ps: polydipsia, polyphagia, and polyuria.

  • Polydipsia: excessive thirst
  • Polyphagia: excessive hunger
  • Polyuria: excessive urination

Hyperglycemic patients will also have warm skin that is very dry. Their breath may have a fruity odor, indicative of seriously high blood sugar levels. And their breathing will tend to be rapid, indicating that they are experiencing Kussmaul's respirations — a compensatory mechanism for metabolic acidosis. Fatigue is another symptom of hyperglycemia.

Treatment for hyperglycemia

Cool Chicken Skin — warm and dry...sugar is high!

A patient with hyperglycemia should be treated with insulin, and the provider should be notified immediately.

Full Transcript

Hi, I'm Meris, and in this video, we're going to be talking about gestational diabetes mellitus. This is super duper important for you to have a really good grasp of during your maternity course because there's a lot of important patient teaching for a patient with gestational diabetes. And also, there are important things to know about how it impacts the baby. So I'm going to be following along using our maternity flashcards. These are available on our website,, if you want to get a set for yourself, and if you already have one, I would absolutely invite you to follow along with me. All right, let's get started.

Okay, so first of all, what is gestational diabetes? Well, it is diabetes during pregnancy, and this is in someone who is not diabetic to start with. So your patient with gestational diabetes is going to have impaired glucose tolerance during pregnancy.

So what are the risk factors? Well, kind of the same for diabetes mellitus otherwise. So for like type 2, for instance. So obesity, if your patient had gestational diabetes in a prior pregnancy, they're at risk, a strong family history of diabetes or gestational diabetes, hypertension, all of those things are going to put your patient more at risk.

Now, signs and symptoms, your patients are usually going to be asymptomatic. This is why we actually screen for this. But same signs and symptoms as with with diabetes otherwise. Polyuria and polydipsia - excessive urination, excessive thirst - those are going to be your most common findings in pregnancy. However, remember that pregnancy is going to cause us to urinate more frequently than normal anyway so that it can be really hard to distinguish.

Now what do we do? Well we actually screen for it. So you're going to see that your patients will have an oral glucose tolerance test, an OGTT, and it's a one hour test that is performed. And this is performed to screen for gestational diabetes. If they fail the one hour, they will do the three hour test, and then that is going to be the diagnostic test for gestational diabetes.

Now the treatment, of course, as with everything, we're going to talk about lifestyle modifications, increasing exercise, changing the diet to have fewer carbs in it, and we're going to teach our patients how to monitor their own blood glucose. Insulin may be required. Most oral diabetic medications are contraindicated in pregnancy, so for that reason insulin is typically the go to. Not everyone requires it, though. With lifestyle modifications, your patients may be able to keep their blood sugars in that goal range, and that would be great.

Now complications. So first and foremost is fetal macrosomia. So macro meaning large and soma meaning body. So a large body size in the newborn. So that is going to be a sign and symptom too that perhaps your patient had undiagnosed gestational diabetes if they came in and had a very large baby.
The other thing, and it's in here in bold red text because it's so important, is that your baby, the baby is at risk for hypoglycemia. So think about it. Why is the baby at risk for hypoglycemia once they're born? Well, they've been getting all of their nutrition from mom. Mom probably had elevated blood sugars even when it's controlled. Even when we're doing well, it's still elevated, right? We have impaired glucose tolerance. Baby was getting a lot of that sugar, and now they are born and no longer getting that sugar. What's going to happen? Their blood sugar will crash. So if you see a baby who is macrosomic, who has a large body size, they are at risk for hypoglycemia because of that, right. You need to make that connection in your brain. Large body size means that they were probably getting a lot of glucose from mom. Now they're born, now they're having extra uterine life, and their blood sugar might crash.

The other thing is that any patient with gestational diabetes is at risk for pre-eclampsia, birth trauma. Again, remember large baby, we could have trauma during birth because of the size of the baby, a C-section, again because of the large baby, and also diabetes following pregnancy. If your patient has gestational diabetes, they need to be monitored in the postpartum period to make sure that they return to their baseline. But they are still at higher risk for developing diabetes mellitus afterwards. So they do need to have a repeat oral glucose tolerance test once they are no longer pregnant to make sure that they return to their baseline.

All right, then we're going to talk about hypoglycemia and hyperglycemia in your patient with gestational diabetes. Now there's not really too much that's different from this just in any patient with diabetes, but we're just going to cover it again.

Remember hypoglycemia? That means low blood sugar, right? So low blood sugar. Your patient is going to have this really characteristic look to them. They are going to be diaphoretic. So sweaty, they're going to be really sweaty. They're going to have cold and clammy skin. And you'll know exactly what that feels like. If you've ever touched somebody with cold, clammy skin, it's a very unique feeling. They may have a headache. They may have shakiness, right? They may say, I feel really shaky. They could have blurred vision. And then, of course, hunger.

So the cool chicken way to remember this is "Cold and clammy, I need candy."

So that means if I see a patient with cold and clammy skin that I should be thinking hypoglycemia, I need to treat them with sugar.

So the treatment, of course, is going to be 15 grams of a quickly absorbed glucose, something like a juice or soda or milk, something that has that glucose in it. And then we want to give them a protein snack after that as well. If I just replace the glucose, it will go away and they will crash again. I need to give them protein to have that long sustained energy source.

Now hyperglycemia, my blood sugar is too high. The hallmark signs here are the three P's: polydipsia, polyphagia, and polyuria. So polydipsia is excessive thirst, polyphagia is excessive hunger, and polyuria is excessive urination. So that is going to be your classic three signs there. But remember, your patients will also have warm skin that is very dry. They may have a fruity odor to their breath. That's a really important finding - that means like we have seriously high blood sugar levels - and rapid breathing. Think about it. What is that rapid breathing called? What's the name for it? Pause it. Think about it. I hope you paused it. That rapid breathing is called Kussmaul's respirations, and it is a compensatory mechanism for metabolic acidosis. And of course, fatigue is going to be another finding as well.

We have a cool chicken way to remember the findings of hyperglycemia. It's, "If my skin is warm and dry, my sugar's high."

So warm and dry, sugar's high. That means if you find your patient with warm, dry skin, you should be thinking they have hyperglycemia. "Cold and clammy, I need candy." "Warm and dry, sugar's high." I hope that is helpful for you. I know that that has helped me extensively in nursing school and in clinical practice, because it really does help you to identify the findings of these conditions.

All right, I hope that review was nice and comprehensive for you. If you enjoyed it, please like this video so that I know, and if you have a great way to remember something, I want to hear it in the comments below. And I'm sure that everybody else watching this video does, too. Be sure to subscribe to the channel so that you can be the first to know when the next video comes out. Thanks so much, and happy studying.

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