Gestational Diabetes

A person holding their pregnant stomach.

Gestational diabetes is a temporary type of diabetes (different from type 1 and type 2) that occurs in pregnant women. Its onset tends to be around the 24th week of pregnancy. Gestational diabetes occurs when pregnant women, specifically those who have never had diabetes before, experience high blood glucose levels during pregnancy. This condition affects about 9.2% of all pregnant women and is one of the most common health problems that pregnant women face. After the woman gives birth, her blood glucose levels usually return to normal.

While the exact cause of gestational diabetes is not entirely known, researchers have some basic knowledge about the disease. During pregnancy, the placenta supplies certain hormones to the fetus to help it grow and develop. These hormones, while necessary, can have some negative side effects on the woman’s body as they interfere with her levels of insulin. Insulin helps regulate blood sugar by taking glucose out of the bloodstream and into the cells, where it is used for energy (see picture).  Because these prenatal hormones block the action of the mother’s insulin, her body becomes less receptive to insulin, a problem called insulin resistance. Once someone has developed insulin resistance, their body has to work even harder to get the glucose out of the bloodstream and into the cells. In order to do this, their body must produce much higher levels of insulin than normal, hoping that at least some of the insulin will make it into the cells where it can help pull the glucose out of the blood. Producing such high levels of insulin puts a major strain on the mother’s pancreas. After an extended period of time, this can cause damage to the pancreas and can even cause the pancreas to fail altogether. In the case of gestational diabetes however, the pancreas is usually not under strain for a long enough period of time to cause such damage. Pancreatic failure is much more common in people with chronic type 2 diabetes who have had the disease for many years.

Effects on the Fetus

Once the pregnant woman becomes insulin resistant, the insulin she produces does not effectively remove glucose from the blood and bring into the cells. So much glucose remains in her bloodstream that she develops what is commonly referred to as “high blood sugar.” This extra sugar in her blood then crosses the placenta and raises the fetus’s blood sugar. Now that the fetus has high levels of glucose in its blood, its pancreas needs to produce more insulin in order to transfer the glucose from the blood to the cells. The extra glucose that consequently enters the cells is then stored as fat, because the baby simply does not need so much sugar for immediate energy. Because of the extra fat storage, the fetus becomes larger than normal, a condition called macrosomia (see picture). Carrying such a large baby often makes delivery even more difficult for the mother and usually requires a C-section. Babies born to women with gestational diabetes are likely to suffer damage to their shoulders if their mothers elect to not have a C-section and birth them vaginally.

Because the baby has been exposed to so much glucose in the womb, it has learned to secrete a lot of insulin. This means that the baby is likely to have low blood glucose when it is born because it no longer has the high blood glucose from its mother but it still has the high insulin levels. The baby can also develop breathing problems and has a slightly higher chance of dying before birth or soon after birth. Babies born to women with gestational diabetes are also at a greater risk for developing obesity and type 2 diabetes later in life because their bodies have learned early on to be insulin resistant and to store fat more readily.

Effects on the Mother

A pregnant woman sitting beside a doctor in a white coat. They are facing each other.

A woman who experiences gestational diabetes has high blood sugar which can have negative effects on her body. Short term high blood sugar does not result in significant organ damage but it can make you feel tired, weak, thirsty, and make you susceptible to infections. It also can result in depression and blurry vision.  Over the long term, chronic high blood sugar can cause diseases of the eye, including retinopathy and blindness. It also results in kidney damage, general nerve damage throughout the body, and serves as a precursor to heart disease. These long-term effects usually do not apply to women with gestational diabetes though because they do not have the condition long enough; here, long-term effects take years to develop and gestational diabetes only lasts for a couple of months.

Pregnant women with gestational diabetes are also more likely to develop high blood pressure during their pregnancy and a condition called preeclampsia, a potentially fatal pregnancy complication. Because the woman becomes resistant to insulin, she is also at a slightly greater risk for developing type 2 diabetes later in life, once the pregnancy is over.

Who Gets Gestational Diabetes?

Gestational diabetes is more common in women who:

  • Are overweight when they become pregnant
  • Have had gestational diabetes before
  • Have given birth to a baby weighing more than 9 pounds
  • Have a parent, brother, or sister with type 2 diabetes
  • Have prediabetes, meaning your blood glucose levels are higher than normal yet not high enough for a diagnosis of diabetes
  • Are African American, American Indian, Asian American, Hispanic/Latina, or Pacific Islander American
  • Have a hormonal disorder called polycystic ovary syndrome, also known as PCOS


Women who are significantly overweight, with a BMI of 30 or higher, are at a greater risk for developing gestational diabetes. Women who may be at risk for developing this condition can take steps to have a healthier pregnancy by doing these simple things:

  • Lose excess weight before pregnancy – It is important to try and begin your pregnancy in as healthy of a condition as possible in order to minimize your risk of complications and conditions like gestational diabetes.
  • Make healthier food choices – Try to decrease the amount of fat and sugar you are eating and focus on foods that are high in fiber and protein.
  • Get more exercise – Both before and during pregnancy, aim for at least 30 minutes of exercise each day.


A glucose monitor surrounded by colorful candy.

Most women with this condition will have a healthy baby as long as they monitor their blood glucose levels regularly and watch what they eat. Treatment for this condition includes a combination of special meal plans, scheduled physical activity, daily blood glucose monitoring, and insulin injections.

The American Diabetes Association suggests the following numbers as a guidelines for blood glucose levels for women with gestational diabetes:

  • Before a meal: 95mg/dl or less
  • 1-hour after a meal: 140mg/dl or less
  • 2-hours after a meal: 120 mg/dl or less

Following a healthy meal plan that is not too high in carbohydrates and sugars is key to maintaining ideal blood glucose levels. If you or your partner are pregnant, consult a medical professional for specific guidelines on staying healthy during pregnancy, including how much sugar to eat and how much exercise to engage in. Treating gestational diabetes is so important because if it is left untreated, it can negatively affect both the mother and the baby.


  1. “What Is Gestational Diabetes?” American Diabetes Association. N.p., 20 June 2014. Web. 15 Oct. 2015.
  2. “How to Treat Gestational Diabetes.” American Diabetes Association. N.p., 29 Apr. 2014. Web. 16 Oct. 2015.
  3. “Gestational Diabetes.” Mayo Clinic. N.p., 25 Apr. 2014. Web. 16 Oct. 2015.
  4. “Causes of Preeclampsia.” Preeclampsia Foundation. N.p., 2015. Web. 16 Oct. 2015.
  5. “What I Need to Know about Gestational Diabetes.” National Institute of Diabetes and Digestive and Kidney Diseases. U.S. Department of Health and Human Services, Aug. 2013. Web. 23 Nov. 2015.

Last Updated December 3, 2015.