What is diabetes?

Diabetes is a condition in which the body can't make enough insulin, or can't use insulin normally. Insulin is a hormone. It helps sugar (glucose) in the blood get into cells of the body to be used as fuel. When glucose can’t enter the cells, it builds up in the blood. This leads to high blood sugar (hyperglycemia).

High blood sugar can cause problems all over the body. It can damage blood vessels and nerves. It can harm the eyes, kidneys, and heart. In early pregnancy, high blood sugar can lead to birth defects in a growing baby.

There are 3 types of diabetes:

• Type 1 diabetes. This is an autoimmune disorder. The body's immune system damages the cells in the pancreas that make insulin.

• Type 2 diabetes. This is when the body can’t make enough insulin or use it normally. It’s not an autoimmune disease.

• Gestational diabetes. This is a condition in which the blood glucose level goes up and other diabetic symptoms appear during pregnancy in a person who hasn't been diagnosed with diabetes before. It happens in about 3 in 100 to 9 in 100 pregnant people.

What causes diabetes during pregnancy?

Some people have diabetes before they get pregnant. This is called pregestational diabetes. Other people may get a type of diabetes that only happens in pregnancy. This is called gestational diabetes. Pregnancy can change how a person's body uses glucose. This can make diabetes worse or lead to gestational diabetes. 

During pregnancy, an organ called the placenta gives a growing baby nutrients and oxygen. The placenta also makes hormones. In late pregnancy, the hormones estrogen, cortisol, and human placental lactogen can block insulin. When insulin is blocked, it’s called insulin resistance. Glucose can't go into the body’s cells. The glucose stays in the blood and makes the blood sugar levels go up.

Who is at risk for diabetes during pregnancy?

The risk factors for diabetes in pregnancy depend on the type of diabetes:

• Type 1 diabetes often occurs in children or young adults, but it can start at any age.

• Overweight people are more likely to have type 2 diabetes. 

• Overweight people are more likely to have gestational diabetes. It’s also more common in people who have had gestational diabetes before. And it’s more common in people who have a family member with type 2 diabetes. People with twins or other multiples are also more likely to have it.  

What are the symptoms of diabetes during pregnancy?

There are no common symptoms of diabetes during pregnancy. Most people don't know they have it until they get tested. 

How is diabetes during pregnancy diagnosed?

Nearly all pregnant people who don't have diabetes are screened for gestational diabetes between 24 and 28 weeks of pregnancy. A glucose screening test is given during this time. For the test, you drink a glucose drink and have your blood glucose levels tested after 2 hours.

If this test shows a high blood glucose level, a 3-hour glucose tolerance test will be done. If results of the second test are not normal, gestational diabetes is diagnosed.

How is diabetes during pregnancy treated?

Treatment will depend on your symptoms, your age, and your general health. It will also depend on how severe the condition is.

Treatment focuses on keeping blood glucose levels in the normal range, and may include:

• A careful diet with low amounts of carbohydrate foods and drinks

• Exercise

• Blood glucose monitoring

• Insulin injections

• Oral medicines for hypoglycemia 

What are possible complications of diabetes during pregnancy?

Most complications happen in people who already have diabetes before they get pregnant. Possible complications include:

• Need for insulin injections more often

• Very low blood glucose levels, which can be life-threatening if untreated

• Ketoacidosis from high levels of blood glucose, which may also be life-threatening if untreated

People with gestational diabetes are more likely to develop type 2 diabetes in later life. They are also more likely to have gestational diabetes with another pregnancy. If you have gestational diabetes, you should get tested a few months after your baby is born and every 3 years after that. 

Possible complications for the baby include:

• Stillbirth (fetal death). Stillbirth is more likely in pregnant people with diabetes. The baby may grow slowly in the uterus due to poor circulation or other conditions, such as high blood pressure or damaged small blood vessels. The exact reason stillbirths happen with diabetes is not known. The risk of stillbirth goes up in women with poor blood glucose control and with blood vessel changes.

• Birth defects. Birth defects are more likely in babies of people who have diabetes. Some birth defects are serious enough to cause stillbirth. Birth defects usually occur in the first trimester of pregnancy. Babies of people with diabetes may have major birth defects in the heart and blood vessels, brain and spine, urinary system and kidneys, and digestive system.

• Macrosomia. This is the term for a baby that is much larger than normal. All of the nutrients the baby gets come directly from the pregnant person's blood. If the person's blood has too much sugar, the pancreas of the baby makes more insulin to use this glucose. This causes fat to form and the baby grows very large.   

• Birth injury. Birth injury may occur due to the baby's large size and difficulty being born.

• Hypoglycemia. The baby may have low levels of blood glucose right after delivery. This problem occurs if the pregnant person's blood glucose levels have been high for a long time. This leads to a lot of insulin in the baby’s blood. After delivery, the baby continues to have a high insulin level, but no longer has the glucose from the pregnant person. This causes the newborn's blood glucose level to get very low. The baby's blood glucose level is checked after birth. If the level is too low, the baby may need glucose in an IV.

• Trouble breathing (respiratory distress).  Too much insulin or too much glucose in a baby's system may keep the lungs from growing fully. This can cause breathing problems in babies. This is more likely in babies born before 37 weeks of pregnancy.

• Preeclampsia. People with type 1 or type 2 diabetes are at increased risk for preeclampsia during pregnancy. To lower the risk, they should take low-dose aspirin (60 mg to150 mg a day) from the end of the first trimester until the baby is born.

Can diabetes during pregnancy be prevented?

Not all types of diabetes can be prevented. Type 1 diabetes often starts when a person is young. Type 2 diabetes may be prevented by losing weight. Healthy food choices and exercise can also help prevent type 2 diabetes.

How is diabetes during pregnancy managed?

Special testing and keeping track of the baby may be needed for pregnant people with diabetes, especially those who are taking insulin. This is because of the increased risk for stillbirth. These tests may include:         

• Fetal movement counting. This means counting the number of movements or kicks in a certain period of time, and watching for a change in activity.

• Ultrasound. This is an imaging test that uses sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to look at blood flow through blood vessels.

• Nonstress testing. This is a test that measures the baby’s heart rate in response to movements.

• Biophysical profile. This is a measure that combines tests, such as the nonstress test and ultrasound to check the baby's movements, heart rate, and amniotic fluid.

• Doppler flow studies. This is a type of ultrasound that uses sound waves to measure blood flow.

A baby of a pregnant person with diabetes may be delivered vaginally or by cesarean section. It will depend on your health, and how much your pregnancy care provider thinks the baby weighs. Your pregnancy care provider may advise a test called amniocentesis in the last weeks of pregnancy. This test takes out some of the fluid from the bag of waters. Testing the fluid can tell if the baby's lungs are mature. The lungs mature more slowly in babies whose parent has diabetes. If the lungs are mature, the healthcare provider may advise induced labor or a cesarean section delivery.

Key points about diabetes during pregnancy

• Diabetes is a condition in which the body can't produce enough insulin, or it can't use it normally.

• There are 3 types of diabetes: type 1, type 2, and gestational diabetes.

• Nearly all pregnant people without diabetes are screened for gestational diabetes between 24 and 28 weeks of pregnancy.

• Treatment for diabetes focuses on keeping blood sugar levels in the normal range.

• People with gestational diabetes are more likely to develop type 2 diabetes in later life. Follow-up testing is important.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.