Gestational diabetes

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Gestational diabetes is a disorder characterized by abnormally high levels of blood glucose (also called blood sugar) during pregnancy. Affected women do not have diabetes before they are pregnant, and most of these women go back to being nondiabetic soon after the baby is born. The disease has a 30 to 70 percent chance of recurring in subsequent pregnancies. Additionally, about half of women with gestational diabetes develop another form of diabetes, known as type 2 diabetes, within a few years after their pregnancy.

Gestational diabetes is often discovered during the second trimester of pregnancy. Most affected women have no symptoms, and the disease is discovered through routine screening at their obstetrician's office. If untreated, gestational diabetes increases the risk of pregnancy-associated high blood pressure (called preeclampsia) and early (premature) delivery of the baby.

Babies of mothers with gestational diabetes tend to be large (macrosomia), which can cause complications during birth. Infants whose mothers have gestational diabetes are also more likely to develop dangerously low blood glucose levels soon after birth. Later in life, these individuals have an increased risk of developing obesity, heart disease, and type 2 diabetes.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

The causes of gestational diabetes are complex. This condition results from a combination of genetic, health, and lifestyle factors, some of which have not been identified.

A hormone called insulin is important in the development of gestational diabetes. Insulin, which is produced in the pancreas, controls how much glucose (a type of sugar) is passed from the blood into cells to be used as an energy source. Under normal conditions, when blood glucose levels are high (such as after a meal), the pancreas releases insulin to move the excess glucose into cells, which reduces the amount of glucose in the blood.

As a normal part of pregnancy, women develop a reduced ability to respond to the effects of insulin, known as insulin resistance. This process ensures that there is enough glucose to provide energy for the growing fetus. As insulin resistance develops, more and more insulin is needed to keep blood glucose levels within the normal range. As a result, insulin-producing cells in the pancreas (called beta cells) make larger amounts of insulin. These cells are usually able to keep up with the body's demand for insulin, and so most pregnant women do not develop gestational diabetes. However, in some women, pancreatic beta cells are unable to increase production of insulin enough to keep blood glucose levels within the normal range. The result is a rise in blood glucose levels (hyperglycemia) that characterizes gestational diabetes.

Common variations (polymorphisms) in several genes have been associated with the risk of developing gestational diabetes. Because they are common, these variations can be present in people with gestational diabetes and in those without. It is the combination of these changes that helps determine a woman's likelihood of developing the disease. Although little is known about the genetics of gestational diabetes, studies suggest that the genes associated with this form of diabetes overlap with those associated with type 2 diabetes. These genes are involved in the development or function of insulin-producing beta cells in the pancreas or play a role in insulin resistance.

Genetic variations likely act in combination with health and lifestyle factors to influence a woman's overall risk of developing gestational diabetes. Risk factors include having a previous pregnancy affected by gestational diabetes, being older (particularly over age 35) during pregnancy, or having previously had a baby who was large (over 9 pounds) at birth. Other health conditions that predispose to the disease include overweight or obesity, a hormonal imbalance called polycystic ovary syndrome (PCOS), and prediabetes (higher-than-normal blood glucose levels that do not reach the cutoff for diabetes). Many of the risk factors for gestational diabetes are the same factors that increase the risk of developing type 2 diabetes.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Gestational diabetes is a complex disease without a clear pattern of inheritance. However, many affected individuals have at least one close family member, such as a parent or sibling, with this disease or another form of diabetes (most commonly type 2 diabetes).

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

In the United States, up to 14 percent of all pregnancies are affected by gestational diabetes. The prevalence of gestational diabetes has been increasing rapidly over the past few decades (a trend similar to the increase in obesity and type 2 diabetes).

The risk of developing gestational diabetes varies by ethnic background. Women of Native American, Asian, Hispanic, or African American heritage are more likely to be diagnosed with the disease than are non-Hispanic white women.

Which doctor should you see?

The suggested department for discussing Gestational diabetes is Diabetology, with a endocrinologist / diabetologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• What type of glucose problem has been confirmed?
• What are the individual monitoring and follow-up goals?
• If treatment can cause low glucose, what response plan should be taught?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.