Gestational diabetes mellitus (GDM) is a type of diabetes that can develop during pregnancy. It generally occurs in pregnant women who’ve had no previous history of metabolic conditions prior to pregnancy.
If left untreated, gestational diabetes can lead to pregnancy complications for both mother and baby. According to statistics from the Centers for Disease Control and Prevention (CDC), the national prevalence of gestational diabetes is around six percent.
Sadly, around 50 percent of women who develop gestational diabetes during pregnancy go on to develop long-term insulin resistance and type 2 diabetes.
Some women are at an even higher risk of developing gestational diabetes. In this article, we explore some of the most prevalent risk factors.
What Is Gestational Diabetes?
Diabetes mellitus refers to a set of chronic metabolic conditions that affect the body’s ability to produce or regulate insulin effectively. It is the seventh leading cause of death in the United States alone.
Medically, diabetes is divided into three main subgroups:
- Type 1 diabetes – Insulin-dependent diabetes occurs when the body is unable to produce enough insulin. Daily shots of insulin are required.
- Type 2 diabetes – More common, non-insulin-dependent diabetes develops when the body is unable to use insulin effectively, sometimes due to insulin resistance.
- Gestational diabetes – The most common medical complication of pregnancy, according to the American College of Obstetricians and Gynecologists (ACOG), it develops when the body is unable to utilize or produce insulin properly.
Gestational Diabetes and Insulin
Insulin is a vital hormone that helps maintain homeostasis when it comes to blood glucose levels, also known as blood sugar. Produced by the pancreas, insulin is a key part of metabolism.
Carbohydrates and other simple sugars are broken down by our body into glucose to be stored and used for cellular fuel. Glucose enters the bloodstream and gets pushed into the cells with the help of insulin.
When blood glucose levels get too high, insulin is supposed to help regulate this spike and drive levels back down. Unfortunately, this process can get interrupted by decreased insulin sensitivity (also called insulin resistance). Insulin sensitivity refers to how well the body’s cell responds to insulin.
In the case of gestational diabetes, insulin resistance develops and the body’s ability to regulate blood sugar levels is interrupted.
What Causes Gestational Diabetes?
Most researchers believe gestational diabetes is somehow tied to an overproduction of hormones by the placenta that occurs during the course of pregnancy.
Some insulin resistance is expected during pregnancy, usually as a result of hormonal changes and weight gain. However, there are several factors that can put women at an increased risk of gestational diabetes.
Common Risk Factors for Gestational Diabetes
Generally, most healthcare professionals perform risk assessments for gestational diabetes during early prenatal visits and in later trimesters. Certain risk factors can increase a woman’s chance of developing gestational diabetes — let’s take a look at the most common.
Being Overweight or Obese
One of the biggest risk factors when it comes to developing gestational diabetes is obesity. Generally, this is determined by body mass index (BMI). This is a measurement of body fat percentage based on body weight and height, and is usually part of early screening tests during prenatal care visits.
BMI Categories
| Underweight | Below 18.5 |
| Normal Weight | Between 18.5 to 24.9 |
| Overweight | Between 25 to 29.9 |
| Obese | 30 or greater |
Those who are overweight or obese prior to pregnancy generally have an increased insulin resistance to begin with. So, a higher BMI in early pregnancy (greater than 25) does increase the risk of gestational diabetes.
Generally, this goes hand in hand with a sedentary lifestyle and poor nutrition. So, being at a healthy weight going into pregnancy puts many women at an advantage when it comes to avoiding insulin resistance and gestational diabetes.
Maternal Age of 25 Years of Age or Older
Outside of obesity, maternal age is one of the most important independent risk factors for gestational diabetes. In terms of age, women who are 25 years of age or older are at a greater risk than younger women.
One systematic review in obstetrics research found that for every one-year increase in age (from 18 years), the risk of gestational diabetes increased by nearly 8 percent. When you combine obesity with age, the risks increase even more.
Family History of Diabetes
Family history of metabolic disease also has a role to play when it comes to gestational diabetes. In fact, the relationship between family health history and diabetes has been well established.
This involves close family members. If your mother, father, or siblings have diabetes, your risk for developing prediabetes or type 2 diabetes increases. However, this is not set in stone. In spite of family history, many lifestyle changes can help prevent diabetes and even reverse prediabetes.
Prediabetes Diagnosis
Prediabetes is characterized by higher than normal levels of blood sugar. This “pre” means that blood sugar levels are not high enough to be considered type 2 diabetes.
Millions of adults in the United States are considered prediabetic, many of whom are totally unaware because there are generally no noticeable symptoms.
Prediabetes going into pregnancy can put you at greater risk of developing gestational diabetes. Not only that, but it can also increase your risk of developing type 2 diabetes, which can contribute to cardiovascular disease (heart disease), stroke, and kidney disease down the road.
A Previous Gestational Diabetes Diagnosis
Having gestational diabetes in a previous pregnancy greatly increases your chances of developing it again. Of course, gestational diabetes in previous pregnancies could have had its own risk factors, like the ones we’ve already discussed above.
A previous diagnosis of gestational diabetes could point to a chronic issue of insulin resistance. This is why it is important to provide healthcare professionals with a detailed medical history during early screening tests in order to develop a diabetes care plan.
Previously Given Birth to Larger Baby
Women who have given birth to large babies, 9 pounds or greater, are at an increased risk for developing gestational diabetes. This is known as infant macrosomia. This occurs due to the increased levels of insulin resistance during pregnancy.
Blood glucose is passed through the placenta to the baby during fetal circulation. Research has shown that infants of women with gestational diabetes are at an increased risk of becoming overweight at a young age.
Other Health Problems
There are associated health issues that have also been linked to an increased risk of gestational diabetes, such as high blood pressure (hypertension). This is known as preeclampsia when it occurs during pregnancy.
A hormonal disorder known as polycystic ovary syndrome (PCOS) is another health condition that could increase the chances of gestational diabetes. This occurs due to the hormone dysfunctions and increases in insulin resistance that are common in PCOS.
Being Part of Higher Risk Ethnic Groups
According to the CDC, there are certain people groups that are at an increased risk for developing gestational diabetes. Ethnic groups with a higher prevalence of gestational diabetes include:
- African Americans
- Hispanic or Latino Americans
- Asian Americans
- American Indians or Alaska Natives
- Pacific Islanders
Symptoms and Complications of GDM
There are many women who experience no symptoms of gestational diabetes and go on to have a healthy pregnancy. However, for those that do, these symptoms typically can include:
- General fatigue
- Excessive thirst and hunger
- Frequent urination
- Increased weight gain
Some complications and pregnancy outcomes can include:
- Stillbirth
- Excessive birth weight
- Preterm delivery (early gestation)
- Low blood sugar in the infant at birth
- Increased risk of cesarean delivery (C-section)
- Postpartum type 2 diabetes
Testing for Gestational Diabetes
Prenatal care screenings should be early and often in order to stay on top of gestational diabetes symptoms. Many times, oral glucose tolerance tests are used to check for blood glucose levels.
Treatment and Prevention of GDM
In many cases, gestational diabetes may be preventable. Since obesity is the most common risk factor for gestational diabetes, maintaining a healthy weight before and during pregnancy is vital.
In addition, eating healthy food and getting regular physical activity are paramount. Daily exercise could involve low-impact aerobic exercises like walking, yoga, or swimming. It is best to aim for 30 minutes of exercise 3 to 4 times a week.
Healthcare professionals may also prescribe medications like metformin to help control blood sugar levels in those who are pregnant.
The Bottom Line
Gestational diabetes occurs during pregnancy and disrupts how the body responds to and uses insulin. It can lead to serious pregnancy complications if left untreated.
While there are several risk factors that put certain individuals at a greater risk for developing gestational diabetes, some are preventable. But they require lifestyle changes.
It is important to follow up with your OBGYN or health care provider before you make any serious changes while pregnant.
References, Studies and Sources:
Gestational Diabetes Mellitus | ACOG
Gestational diabetes mellitus and macrosomia: a literature review | NIH
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Diabetic.org is devoted to producing expert and accurate articles and information for our readers by hiring experts, journalists, medical professionals, and our growing Diabetic.org community. We encourage you to read more about our content, editing, and fact checking methods here. This was fact checked by Camille Freking and medically reviewed by Dr. Angel Rivera.
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