The causes and risks of gestational diabetes

Posted by Cheryl Cranick on Nov 14, 2017 8:29:00 AM
4 minute read

With any pregnancy comes the risk of gestational diabetes. It does not mean you had pre-existing diabetes before becoming pregnant, and it does not mean you will have diabetes after giving birth. However, it is something you should take seriously.

Gestational diabetes is diagnosed when your blood glucose level, also known as blood sugar level, is too high while you are pregnant. Glucose (sugar) exists naturally in every person’s bloodstream and is what provides your body with energy. This sugar comes from your body breaking down the foods that you eat.


Understanding glucose levels

A healthy human body includes a pancreas, which is an organ that supports the digestive system. One function of the pancreas is to produce and release insulin as needed. Insulin is a hormone that helps your body manage its sugar levels from going too high (hyperglycemia) or too low (hypoglycemia). After your body breaks down the sugars from your food, the insulin hormone attaches itself to that sugar, which helps your body absorb the sugar as energy. If you have more sugar in your bloodstream than your body needs, insulin will help your body store that energy to use at a later time.

Although our bodies are designed to function in a certain way, sometimes things go wrong. If a person’s body does not produce enough insulin because of a problem with the pancreas, that person is at risk for diabetes. If a person’s body produces enough insulin but his or her cells do not properly use that insulin — known as insulin resistance — he or she will experience high levels of sugar in the blood. If a person’s glucose level stays too high for too long, he or she risks damage to the nerves and blood vessels, and possible problems with the heart, kidneys, brain or limbs.

A gestational diabetes diagnosis means your body is having difficulty absorbing glucose. This is not due to deficiency in insulin, but is a result of the pregnancy causing your body to become more resistant to the effects of the natural insulin that is produced. This is often due to the many hormone changes your body is experiencing, and may even be due to weight gain during pregnancy.


How gestational diabetes affects pregnancy

During pregnancy, you and your baby share many things, and that includes glucose levels. Therefore, if you have high blood sugar during pregnancy, your baby will too. And just as high blood sugar is bad for your health, it is also harmful to a developing fetus.

If your baby is receiving too much glucose, it will be stored as fat, which can cause certain health complications, such as being born at a larger than normal birth weight — called macrosomia — which can make delivery more difficult. A high blood sugar level during fetal development may cause a fast drop in your baby’s blood sugar after he or she is born. Respiratory and other health issues may also occur. A baby that develops in a high-glucose environment is also at a greater risk for childhood obesity or type 2 diabetes.

In addition to negatively affecting a baby’s health, gestational diabetes can also cause a woman to experience complications during pregnancy such as high blood pressure. A baby born with macrosomia could result in a cesarean section. In some cases, a woman with gestational diabetes may eventually develop type 2 diabetes after her pregnancy, particularly with weight gain.


Risk factors

It is common for any woman to experience some level of insulin resistance later in pregnancy. If you are at risk for gestational diabetes, the condition usually occurs around week 24 to 28 of pregnancy. Most doctors test for it. If your diagnosis of gestational diabetes comes earlier in your pregnancy, you may have had undiagnosed pre-existing diabetes before becoming pregnant.

According to the National Institute of Diabetes and Digestive and Kidney Diseases, risk factors for gestational diabetes include:

  • being overweight
  • having a history of gestational diabetes
  • having a previous baby weighing more than 9 pounds at birth
  • having a family history of diabetes
  • having a pre-existing issue with high blood glucose prior to conception
  • being of a minority ethnic group
  • having a hormonal disorder called polycystic ovary syndrome (PCOS)


Often, there are few or no symptoms of gestational diabetes. Proper monitoring by your health care team during pregnancy will help watch for signs. You can also be an active part of that team. With healthy eating habits and approved exercise, you can lower your risk of developing this condition.

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Clinically reviewed by Alan Fishman, MD

Topics: Maternal-Fetal Medicine, Prenatal