What is gestational diabetes?

Gestational diabetes^[1] is a form of diabetes^[2] that develops during pregnancy (gestation) in women who did not already have diabetes beforehand. The condition’s onset usually occurs during the middle of pregnancy. Like other types of diabetes, gestational diabetes affects the way blood cells use sugar (glucose). It causes high blood sugar and can affect both your pregnancy and your baby’s health. Some women have more than one pregnancy affected by gestational diabetes. Oftentimes, the condition can be managed with healthy lifestyle choices like eating a healthy diet and getting exercise. In some cases, women with gestational diabetes have to take insulin to manage their condition. Blood sugar levels in women with gestational diabetes generally return to normal shortly after giving birth. However, controlling blood sugar during pregnancy can help prevent birth complications and keep a pregnant mother and baby healthy.

How common is gestational diabetes?

According to the American Pregnancy Association^[3], roughly 2–5% of pregnant women develop gestational diabetes. In women with certain risk factors that increase the likelihood of developing gestational diabetes, this number may be as high as 7–9%.

What is diabetes mellitus?

Diabetes mellitus^[4] (generally, diabetes) refers to a group of diseases that prevent the body from properly using glucose. Diabetes is classified into two main types: type 1 and type 2. Type 1 diabetes^[5] occurs when the pancreas (an organ located behind the stomach) produces little to no insulin, a naturally occurring hormone that helps the body use sugar for energy. When the pancreas’ beta cells are damaged, the pancreas does not make enough insulin, so glucose can’t get into the body’s cells to be used as energy. People with type 1 diabetes must inject insulin to control their blood sugar. Type 1 diabetes is the most common form of diabetes in people under 30 but can occur at any age. 10% of people with diabetes are diagnosed with type 1. Type 2 diabetes^[6], also called adult-onset diabetes, occurs when the pancreas makes insulin, but the insulin produced is insufficient or doesn’t work properly. Type 2 diabetes is usually controlled with healthy lifestyle choices. Sometimes, however, treatments can include oral glucose-lowering medications or insulin injections. Type 2 diabetes occurs most often in people who are over 40 years old but can occur even in childhood when one or more risk factors for developing the disease are present. Roughly 90% of people with diabetes have type 2.

What is diabetes insipidus?

Diabetes insipidus^[7] is an uncommon disorder that occurs when the body can’t regulate its fluid levels properly, causing an imbalance of fluids in the body. The condition is less common than diabetes mellitus (type 1 or type 2 diabetes). There are several different types of diabetes insipidus:

• Central diabetes insipidus: Central diabetes insipidus can be caused by a change in the usual production, storage, and release of ADH, a hormone produced by the hypothalamus and stored in the pituitary gland. This is often caused by damage to the pituitary gland or hypothalamus.
• Nephrogenic diabetes insipidus: Nephrogenic diabetes insipidus may be caused by genetic disorders or chronic kidney disorders (and, in some cases, certain medications). It occurs when a defect is present in the kidney tubules (the structures in the kidneys that cause water to be either excreted or reabsorbed), making the kidneys unable to properly respond to ADH.
• Primary polydipsia: This condition (also known as dipsogenic diabetes insipidus) can result from damage to the hypothalamus’ thirst-regulating mechanism. This causes the body to produce large amounts of diluted urine.
• Gestational diabetes insipidus is rare—it only occurs when an enzyme made by the placenta destroys a pregnant woman’s ADH.

Diabetes insipidus can cause extreme thirst (even when drinking plenty of water) and producing large amounts of urine. While there is no cure for diabetes insipidus, some treatments can relieve your thirst and decrease your volume of urination. Common signs and symptoms of diabetes insipidus include:

• Extreme thirst
• Producing a large volume of diluted urine
• Frequent need to get up and urinate at night
• Preference for cold beverages

When serious, diabetes insipidus can cause urine output to be as much as 20 quarts (roughly 19 liters) a day if you’re drinking a lot of fluids (compared to the average healthy adult, who typically urinates an average of 1–2 quarts [1–2 liters] per day). Infants and young children with diabetes insipidus may have the following signs and symptoms:

• Bedwetting
• Heavy, wet diapers
• Trouble sleeping
• Fever
• Vomiting
• Constipation
• Delayed growth
• Weight loss

If you believe yourself to have any form of diabetes, or if you experience any new or worsened symptoms, see your healthcare provider immediately.

Gestational diabetes causes

Researchers don’t know exactly why^[9] some women develop gestational diabetes. However, to understand how gestational diabetes occurs, it can be helpful to understand how pregnancy affects the body’s processing of glucose. When your body digests food, it produces sugar (glucose) that enters your bloodstream. Normally, the pancreas produces insulin in response. This insulin helps move glucose from the bloodstream into your body’s cells, where it is used as energy. The placenta, which connects a baby to the pregnant woman’s blood supply, produces high levels of various other hormones during pregnancy. Almost all of these hormones impair the action of insulin in the body’s cells, causing an increase in your blood sugar. As a result, a modest elevation of your blood sugar after meals is normal during pregnancy. As a baby grows, the placenta produces greater amounts of insulin-counteracting hormones. Gestational diabetes occurs when placental hormones cause a rise in blood sugar to a level that can potentially affect the growth and welfare of a developing baby.

Gestational diabetes risk factors

While any woman can potentially develop gestational diabetes, some are at greater risk. Common risk factors^[10] for gestational diabetes include:

• Age: Women older than age 25 are more likely to develop gestational diabetes than younger women.
• Family or personal health history: Women with prediabetes or who have a close family member (such as a parent or sibling) with type 2 diabetes have a higher risk of developing gestational diabetes. Women are also more likely to develop the condition if they had it during a previous pregnancy, if they delivered a baby who weighed more than 9 pounds (4.1 kg), or if they had an unexplained stillbirth.
• Excess weight: Women with a body mass index (BMI)^[11] of 30 or higher have an increased likelihood of developing gestational diabetes.
• Race/ethnicity: While it is unclear why, women who are African-American, Hispanic, Indigenous American, or Asian are at higher risk of developing gestational diabetes than caucasian women.

What is prediabetes?

Prediabetes^[12] is a precursor of diabetes. People with prediabetes have blood sugar levels that are higher than normal but not yet high enough to be classified as type 2 diabetes^[13]. Prediabetes can affect both adults and children. If people with prediabetes don't make healthy lifestyle changes, they are likely to progress toward developing type 2 diabetes. Some people with prediabetes may already experience some of the signs, symptoms, and complications associated with type 2 diabetes. Not everyone with prediabetes progresses to type 2 diabetes. Making healthy lifestyle choices can help return blood sugar levels to normal.

Gestational diabetes symptoms

For most women, gestational diabetes doesn’t cause any noticeable signs and symptoms^[14]. However, in some cases, gestational diabetes can cause the following signs and symptoms^[15]:

• Sugar in urine (which is revealed in a test administered by a healthcare provider)
• Unusually increased thirst
• Frequent urination
• Fatigue
• Nausea
• Frequent vaginal, bladder, and skin infections
• Blurred vision

Gestational diabetes complications

Most women with gestational diabetes deliver healthy babies despite their condition. However, if gestational diabetes isn’t carefully managed, it can lead to uncontrolled blood sugar levels that may cause problems for both the woman and her baby. If you have gestational diabetes, your baby may be at an increased risk of:

• Excessive birth weight: When excess glucose in the bloodstream crosses the placenta, it triggers the baby’s pancreas to make extra insulin. This can cause a baby to grow too large (a condition called fetal macrosomia^[16], which indicates a birth weight of more than 8 pounds, 13 ounces). Babies that weigh 9 pounds or more are likely to become wedged in the birth canal, sustain injuries, or require a C-section birth.
• Early (preterm) delivery and respiratory distress syndrome: High blood sugar in a pregnant woman may increase the risk of early labor and delivery (if the baby is very large, a healthcare provider may recommend early delivery). Babies that are born early may experience respiratory distress syndrome—a condition that makes breathing difficult—and may need help breathing until their lungs mature and become stronger. Babies of women with gestational diabetes may also experience respiratory distress syndrome even if they aren’t born early.
• Low blood sugar (hypoglycemia^[17]): Some babies of women with gestational diabetes may develop low blood sugar (called hypoglycemia) shortly after birth because their insulin production is elevated. Severe episodes of hypoglycemia in babies may cause seizures.
• Type 2 diabetes later in life: Babies of women who had gestational diabetes have an increased risk of developing obesity and type 2 diabetes later in life.

If left untreated, gestational diabetes can result in a baby’s death before or shortly after birth. Gestational diabetes may also cause complications—it can increase a woman’s risk for:

• High blood pressure (hypertension^[18]) and preeclampsia^[19]: Gestational diabetes raises the risk of developing high blood pressure and preeclampsia, a serious complication of pregnancy that causes high blood pressure and other symptoms that can put the lives of both the pregnant woman and baby at risk.
• Future diabetes: If a woman has had gestational diabetes, she is at a higher risk of getting it again during future pregnancies. She is also more likely to develop type 2 diabetes with age. However, healthy lifestyle choices can help reduce the risk of future type 2 diabetes—of those women with a history of gestational diabetes who reach their ideal weight after giving birth, fewer than 25% eventually develop type 2 diabetes.

It’s important to talk to your healthcare provider if you experience any signs or symptoms of gestational diabetes. He or she will be able to diagnose your condition and provide you with the best course of treatment.