Gestational Diabetes

Gestational diabetes is a form of diabetes that develops during a woman’s pregnancy, typically around the 28th week or later. Despite some similarities, it is not the same as the type 2 diabetes that most people are familiar with (although an existing case of type 2 diabetes can certainly affect pregnancy—click here to read about this subject). The basic malfunction in any form of diabetes is higher than normal levels of glucose in the bloodstream, which is referred to as hyperglycemia. So hyperglycemia during pregnancy is the problem that is diagnosed as gestational diabetes.

Causes of Gestational Diabetes

Although there is no conclusive evidence, experts believe pregnant women develop this condition because of changes in their glucose metabolism and insulin resistance caused by pregnancy hormones. The placenta produces many different hormones that help and support the growth of the baby, and one of the effects is a partial blockage of the actions of insulin, which is the major hormone the body uses to regulate blood sugar levels. This partial blockage is referred to as insulin resistance.

The pregnant woman’s body is forced to produce higher and higher amounts of insulin (up to three times higher, according to the American Diabetes Association) to keep her blood glucose levels in the normal range. If the body cannot make enough insulin to overcome this blocking effect, then hyperglycemia occurs, and this condition is called Gestational Diabetes.

According to the American Diabetes Association (ADA), gestational diabetes affects approximately 4 percent of all pregnant women within the United States, or more than 135,000 women each year. While this condition typically goes away after birth, women with gestational diabetes mellitus have a 45 percent risk of recurrence with future pregnancies and an increased risk of developing type 2 diabetes later in life.

Symptoms of Gestational Diabetes

Symptoms of gestational diabetes are typically non-existent during the early stages of pregnancy. This is one reason why pregnant women are usually given a glucose screening test (see below). If your glucose levels are high on the screening test, you will be given a more accurate diagnostic test. Most women report no symptoms throughout their pregnancies, but symptoms may include:

Diagnosing Gestational Diabetes

Almost all women are first offered a glucose screening test at some point during their pregnancy, usually between the 24th and 28th week of gestation. It might also be done at the beginning of the pregnancy if you have risk factors for the condition. At the start of the screening, you will be given a glucose solution to drink; this solution contains 50 grams of pure glucose. An hour later, a blood sample will be taken and analyzed. If the test reveals high glucose levels, you will be asked to return for a second test called the three-hour glucose tolerance test (GTT). This test measures your body’s ability to use glucose, and helps doctors make a proper diagnosis. There are four blood draws for this test.

To prepare for the glucose tolerance test, you may be asked to eat a diet rich in carbohydrates for a couple of days (not too important, since the American diet is very high in carbohydrates already), and then fast the night before the appointment (no food after midnight, but water is okay). The first step of the test is a blood draw to test your fasting glucose level. Then you will be asked to drink a sweet liquid that contains 100 grams of glucose. Blood samples are taken every hour over the course of the next three hours. This is done to measure your glucose levels. After the last blood draw you are done, and can eat whatever you wish. You may want to bring a snack with you to the lab!

Interpretation of results

You have gestational diabetes:

  • If your fasting glucose (i.e., after eight hours with no food) is greater than 126
  • If any two of the four blood glucose levels are elevated

Some obstetrical practitioners are following a new protocol, the 75-gram two-hour GTT. In this case there is no screening test. Each patient has a fasting blood draw, then drinks the solution, and has two more blood draws at one hour and two hours later. A single elevated value means you have gestational diabetes. This version of the test is endorsed by the ADA but not by the American College of Ob/Gyn (ACOG).

Gestational Diabetes Treatment

Often, gestational diabetes can be successfully treated with just a specific type of diet. If you are diagnosed with this condition, your healthcare provider will work with you to create an appropriate diet to maintain normal blood glucose levels or he or she might refer you to a registered dietitian. Most women with gestational diabetes eat three meals a day and a snack before bed.

Calories need to be watched, and meals should be spaced apart accordingly. Fatty foods and cooking methods such as frying should be avoided. These foods can cause you to gain weight, which can cause your blood glucose levels to rise. Exercising regularly is also important for treating this condition, as exercise can keep your weight and glucose levels down.

You will need to test your glucose levels often, using the finger-stick method and a glucose meter. This is called CBG (capillary blood glucose) testing. Your doctor may also administer some tests in the office or at the hospital. This is done to make sure that your diet is successfully maintaining your glucose levels. If your diet fails to control your glucose levels, you may need to go on oral medication or even to take insulin shots throughout the remainder of your pregnancy and labor.

In most cases, glucose levels return to normal after delivery, so oral medication or insulin injections are not needed afterward. However, you are now considered to be at an increased risk for developing type 2 diabetes later in life, so your doctor may recommend glucose-screening tests a couple of months after delivery and during the early stages of any subsequent pregnancies. You will also want to have routine blood tests during future check-ups to be sure your glucose is remaining at a healthy level.

When monitoring your blood glucose levels at home, you will be asked to check them four to six times per day. The first test is done right after you wake up, and it is followed by three or more additional tests, each of which is performed one hour after the start of each meal. Experts believe testing one hour after the beginning of each meal provides the most accurate results. Target blood glucose levels are typically 95 mg/dL or less for the first test of the day (because you have been sleeping for eight hours), and 120 to 140mg/dL for each of the three remaining tests (below 140 for a test conducted an hour after a meal; below 120 for a test conducted two hours after a meal).

Your healthcare provider will emphasize the importance of maintaining normal blood glucose levels. Inactivity, food, stress, and hormones can elevate your blood glucose levels. Exercise, insulin, and specific oral medications can lower them. Physical activity is also known to increase insulin receptor sensitivity and help lower blood sugar levels. It’s very helpful to take a walk right after a meal to help lower the glucose level one hour later.

If you need insulin, human insulin is prescribed. One dose of long-acting insulin before bed is often sufficient (NPH insulin for example) if the only elevated numbers are the fasting glucose levels. If glucose is high after meals, you might need rapid-onset short-acting insulin (like Humalog) before meals.

Complications of Gestational Diabetes

Thankfully, this condition typically goes away once the baby is delivered, since there is no more placenta to produce insulin-blocking hormones. If diagnosed and properly treated, gestational diabetes typically does not cause any problems for Mom or baby. If it is not treated, it can lead to several complications for both Mom and baby.

Complications of untreated or inadequately treated gestational diabetes may include:

Untreated or poorly controlled gestational diabetes can lead to complications for your baby. Although insulin is not connected to the placenta, glucose, and other nutrients are. This means that extra blood glucose goes through the placenta, which gives your baby high blood glucose levels and causes your baby’s pancreas to work extra hard (like your pancreas) to make extra insulin to get rid of the blood glucose. The baby can end up with too much insulin, which can cause certain problems.

The extra glucose going to the baby is stored as fat since it is more than your baby needs to grow and develop. Typically, such babies are born with macrosomia, also known as “big baby syndrome.” Macrosomic babies can experience a variety of health problems throughout their lives, including damaged shoulders during birth. Extra insulin made by the baby’s pancreas can lower his or her blood glucose levels at birth which if not diagnosed and treated promptly can lead to possibly permanent brain damage. These babies are also at a higher risk for developing respiratory problems due to a delay in lung development. Babies born under these circumstances are also susceptible to developing type 2 diabetes as adults.

Risk Factors for Gestational Diabetes

You may be at an increased risk for developing gestational diabetes if:

  • You are over the age of 25
  • You are overweight at the time of conception
  • You have had this condition previously
  • You have had a previous baby weighing nine pounds or more at birth
  • You have a history of poor pregnancy outcomes (multiple miscarriages)
  • You have glycosuria (an abnormal amount of glucose in your urine)
  • You have Polycystic Ovary Syndrome (PCOS)
  • You have a family history of type 2 diabetes mellitus
  • You are ethnically Native American, Mexican, Asian, or East Indian

Living with Gestational Diabetes

Gestational diabetes usually goes away after birth, especially if you take care of yourself properly during your pregnancy. Here are some tips to help you live a normal life with gestational diabetes:

  • Engage in activities that encourage relaxation and deep breathing
  • Get your partner to engage in these same activities, if possible
  • Talk with your partner about ways to limit stress levels in your environment
  • Follow your doctor’s instructions thoroughly
  • Try to be active every day even if it’s just a short walk (But more exercise is better!)
  • Always talk with your doctor before beginning a new exercise or diet program

To learn more about this condition and other forms of diabetes, visit The American Diabetes Association at

This page was last updated on 06/2017

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