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Gestational diabetes requires additional attention during pregnancy, but care and support can keep both the woman and the developing fetus healthy throughout the pregnancy and beyond. Read on to learn more about gestational diabetes. For information on nutrition, exercise, and technology during pregnancy see more resources below. And read our latest article on everything you need to know about gestational diabetes.

Starting Point: Gestational Diabetes Basics

What is gestational diabetes?

Gestational diabetes (also called GDM) is when unusually high blood sugar levels develop during pregnancy, which can cause health complications for the mother and the developing fetus. 

Gestational diabetes often develops in the later stages of pregnancy, and usually disappears after the mother gives birth. During pregnancy, insulin (the hormone that helps cells in the body take up glucose for energy) may not be able to perform its typical role due to interference from hormones produced by the fetus or other chemical changes within the body; usually, a woman’s body will produce additional insulin to compensate. In someone with gestational diabetes, the body’s insulin can’t keep blood glucose levels in a stable range, which leads to higher blood sugar levels and health risks.

Who does gestational diabetes affect?

Each year, up to 14% of pregnant women in the US develop gestational diabetes. Gestational diabetes can occur in pregnant women who have never had diabetes and whose high blood sugar levels are first detected during pregnancy; it’s different from being diagnosed with type 1 or type 2 diabetes before becoming pregnant. If a mother’s blood sugar levels remain elevated after pregnancy, she may have type 1 or type 2 diabetes.

How and when is gestational diabetes diagnosed?

Pregnant women are usually tested for gestational diabetes between weeks 24 and 28 of pregnancy. Healthcare professionals use two methods for diagnosis:

  • Two-part test: This method is common in the US. The mother’s blood glucose will be measured one hour after consuming a sugary drink. If her blood sugar level is higher than 200 mg/dl, an oral glucose tolerance test will be the next step (for reference, 70-120 mg/dl is the target range for someone without diabetes). For the oral glucose tolerance test, the mother will fast (no eating) overnight. Blood sugar levels are then measured while fasting, and then one, two, and three hours after consuming a sugary drink. Gestational diabetes is diagnosed only if this test reveals two or more high blood glucose results.

  • One-part test: With this method, fasting blood glucose levels will be measured, and then again one hour and two hours after the mother consumes a sugary drink. Gestational diabetes is diagnosed if one or more blood sugar measurements are higher than normal.

Who is at risk of developing gestational diabetes?

Risk factors for developing gestational diabetes include:

  • Having obesity or excess weight (a BMI above 25 kg/m2)

  • Being physically inactive

  • A history of gestational diabetes in a previous pregnancy, or a family history of type 2 diabetes or prediabetes

  • Previously giving birth to a baby nine pounds or heavier

  • High blood pressure, polycystic ovary syndrome (PCOS), or a history of heart disease

  • Ethnic background: African-American, Asian American, Hispanic, Native American or Pacific Island

  • Are older than 25

It is possible to have none of these risk factors and still develop gestational diabetes (or to have several of these risk factors and not develop the condition). The condition results from a combination of factors, many of which are beyond any individual’s control. If you are pregnant, speak with your healthcare professional about screening and healthy pregnancy behaviors. 

What are the symptoms of gestational diabetes?

Gestational diabetes often does not have noticeable signs. However, some women may experience increased thirst and urination.

What should someone with gestational diabetes do?

If you are diagnosed with gestational diabetes, it’s important to start carefully managing your blood sugar levels. For most women, the aim is to keep blood glucose levels between 63 mg/dL and 140 mg/dL as much as possible – they need to work with their healthcare team early and often after diagnosis, and determine their personal glucose targets. Treatments will often include strategic meal plans and exercise, and may incorporate medication and available diabetes technology.

  • The California Department of Public Health recommends a carbohydrate-controlled diet with meals and snacks spread two to three hours apart and walking after each meal. 

  • For exercise, healthcare professionals suggest 30-60 minutes of moderately intense cardio and strength training three times per week. 

  • Remember that there are many more factors that affect blood sugar, including sleep, stress, and your environment. Talk with a healthcare professional to come up with an individual approach to managing your blood sugar levels – which may include meal plans, exercise routines, and insulin (if necessary).

Some tools and technologies may be able to help you manage glucose. A continuous glucose monitor (CGM) tracks glucose levels every few minutes throughout the day and night. This information can be exceptionally helpful for staying in your target glucose range, tracking and replicating the factors that create the best environment for mother and child.

How does gestational diabetes affect pregnancy?

If left untreated, the high blood sugar levels associated with gestational diabetes can lead to various issues during pregnancy, such as:

  • Giving birth to a large baby (weighing more than nine pounds), increasing the risk of injury during birth for both the baby and the mother. The chances of requiring a Caesarean section also increase at high birth weights.

  • Increased risk of miscarriage, birth defects, and stillbirths.

  • High blood pressure, which can harm both long-term and short-term health.

  • Preeclampsia, a rare complication characterized by high blood pressure with possible kidney or liver damage. 

How may gestational diabetes affect the baby?

During pregnancy, nutrients from the woman’s bloodstream fuel the baby’s growth. With gestational diabetes, an expectant woman’s high blood glucose can cause the baby to absorb more glucose than it needs. This excess glucose can be stored as additional fat, which can lead to complications at birth and later in life. Other effects include:

  • Heavier than average birthweight (more than 9 pounds). The extra weight could cause shoulder damage during birth.

  • Low blood glucose levels (called neonatal hypoglycemia) due to the extra insulin the baby’s body produces before birth.

  • Difficulty breathing.

  • Higher risk of childhood obesity.

  • Higher risk of developing type 2 diabetes as an adult.

What effects does gestational diabetes have after pregnancy?

  • If blood glucose levels remain high even after giving birth, it’s likely that the mother has type 1 or type 2 diabetes. Talk to a healthcare professional about appropriate screening and follow-up.

  • Women who experience gestational diabetes have an increased likelihood of developing type 2 diabetes later. This risk can be reduced with an appropriate treatment plan, often including strategic nutrition and exercise. 

Does gestational diabetes affect future pregnancies?

Two out of three women diagnosed with gestational diabetes will be diagnosed again in future pregnancies; the more pregnancies a woman has with elevated blood sugar levels, the more likely future pregnancies will bring about similar blood glucose trends. This risk can be reduced through healthy eating habits and regular exercise as well as weight loss if recommended by a healthcare professional.

Other Resources

Please note, this page is not a comprehensive list of all the available resources.