Gestational Diabetes: Causes, Symptoms and Management
Gestational diabetes is a carbohydrate intolerance of variable severity that starts or is first recognized during pregnancy or the inability of the tissues to absorb glucose from the bloodstream during pregnancy due to a lack of the hormone insulin.
guidelines are based on a study of more than 23,000 women in nine countries.
Metzger and the international team concluded that:
- A fasting blood sugar level of 92 or higher,
- A one-hour level of 180 or higher on a glucose tolerance test, or
- A two-hour level of 153 or higher on a glucose tolerance test
All posed serious risks to the mother and the infant. All of these levels had
previously been considered to be in the safe, normal range, and a woman had to
have two high levels before she would be diagnosed with gestational diabetes.
(The study’s lead author Boyd Metzger, MD, the Tom D. Spies Professor of
Metabolism and Nutrition at Feinberg and a physician at Northwestern Memorial
Hospital, and a group of 50 international experts spent about two years
analyzing data from a 2008 study. )
Glucose is a form of sugar that is present in many foods, including sweets, potatoes, pasta, and breads. The body uses glucose to provide energy. It is stored in the liver, muscles, and fatty tissue. The pancreas produces a hormone (a chemical produced in one part of the body, which travels to another part of the body in order to exert its effect) called insulin. Insulin is required to allow glucose to enter the liver, muscles, and fatty tissues, thus reducing the amount of glucose in the blood. In diabetes, blood levels of glucose remain abnormally high. In many forms of diabetes, this is because the pancreas does not produce enough insulin.
In gestational diabetes, the pancreas is not at fault.
Instead, the problem is in the
placenta. During pregnancy, the placenta provides the baby with
nourishment. It also produces a number of hormones that interfere with the
body's usual response to insulin. This condition is referred to as "insulin
resistance." Most pregnant women do not suffer from gestational diabetes,
because the pancreas
works to produce extra quantities
of insulin in order to compensate for insulin resistance. However, when a
woman's pancreas cannot produce enough extra insulin, blood levels of glucose
stay abnormally high, and the woman is considered to have gestational diabetes.
Women at risk:
During the course of pregnancy, up to 1 in 50 women temporarily develop diabetes mellitus.
Women at risk for gestational diabetes include those who:
have a family history of diabetes
have previously given birth to a very large, heavy baby
have previously had a baby who was stillborn, or born
with a birth defect
have an excess amount of amniotic fluid (the cushioning
fluid within the uterus that surrounds the developing fetus)
are over 25 years of age
belong to an ethnic group known to experience higher
rates of gestational diabetes (in the United States, these groups include
Mexican-Americans, American Indians, African-Americans, as well as
individuals from Asia, India, or the Pacific Islands)
have a previous history of gestational diabetes during a
The IADPSG guidelines recommend screening all women at their first
doctor's visit early in pregnancy, using the current criteria to
diagnose diabetes in the general population. The goal here is to
identify diabetes that is already present but not diagnosed. These women
are already diabetic, and care should be started to control their blood
sugar. The guidelines then suggest doing a full glucose tolerance test
in the second trimester of pregnancy, without doing the screen with the
small amount of glucose first.
Most women with gestational diabetes have no recognizable symptoms for this
reason it is recommended that all pregnant women be
screened for gestational diabetes during the 24th and 28th weeks of their
The symptoms are usually mild and not life-threatening
to the pregnant woman like
The current guidelines of the American Diabetes Association
(ADA) recommend screening women in the second trimester of pregnancy (after
about 20-24 weeks of pregnancy). By this point in the pregnancy, the placental
hormones have reached a sufficient level to cause insulin resistance. It
involves the pregnant woman drinking a special solution that contains exactly 50
grams of glucose. An hour later, the woman's blood is drawn and tested for its
glucose level. A level less than 140 mg/dl is considered normal.
When the screening glucose level is over 140 mg/dl, a
special three-hour glucose tolerance test is performed. This involves following
a special diet for three days prior to the test. This diet is set-up to contain
at least 150 grams of carbohydrate each day. Just before the test, the patient
is instructed to eat and drink nothing (except water) for 10-14 hours. A blood
sample is then tested to determine the fasting glucose level. The patient then
drinks a special solution containing exactly 100 grams of glucose, and her blood
is tested every hour for the next three hours. If two or more of these levels
are elevated over normal, then the patient is considered to have gestational
A recent article from an international panel of experts, known as the International Association of Diabetes and Pregnancy Study Group (IADPSG), has suggested new guidelines for diagnosing gestational diabetes. According to them a woman may not need laboratory testing to screen for GDM if she meets all of the following criteria:
less than 25 years old
not a member of a racial or ethnic group with a high prevalence of
diabetes (eg, Hispanic, African, Native American, South or East Asian, or
Pacific Islands ancestry)
a body mass index (BMI) 25
no history of abnormal glucose tolerance
no previous history of adverse pregnancy outcomes usually associated
no known diabetes in first-degree relative
Women who are at a higher risk for GDM usually have one of
the following risk factors:
Treatment for gestational diabetes will depend on the severity of the
diabetes. The goals of treatment are to maintain
glucose levels within normal limits during the duration of the pregnancy,
and ensure the well-being of the fetus.
Mild forms can be treated with diet (decreasing the intake of sugars
and fats, in particular). The overall principles are to
reduce the amount of fat,
simple sugar, and salt and increase the amount of complex
carbohydrates and foods high in
Current American Diabetes Association guidelines advise that less than 30% of
total daily calories should come from fat sources. Protein choices with less fat
are recommended, such as skinless poultry, fish, and lean meats. The recommended
daily allowance is approximately two three-ounce servings of protein a day. A
three-ounce portion of meat is approximately the size of a deck of playing
cards. No more than 10% to 20% of the day's total calories should come from
protein. Approximately 50% to 60% of the day's total calories should come from complex
carbohydrates such as starches and whole-grain breads, with an emphasis on
choices. Foods that are high in carbohydrates provide energy,
vitamins. Food sources of complex carbohydrates and fiber are fruits and
vegetables, whole-grain breads and cereals, dried beans and peas, and lentils
and legumes. Meals should be eaten at approximately the same time every day.
Use sources of simple (concentrated) carbohydrates,
such as table sugar, honey, soda, juice, or syrup, in moderation. Concentrated
sources of carbohydrates cause the blood sugar levels to rise quickly. Exercise
caution when eating simple carbohydrates. A registered dietitian can help you
best decide how to include simple carbohydrates into your diet plan.
ACOG state quite clearly that even if one chooses to restrict caloric intake
no more than 33% of the calories should be removed from the woman's diet.
Here are some other
Eat and drink at least 4 servings of dairy products
calcium-rich foods a day to help ensure that you are getting 1200 mg. of
calcium in your daily diet.
Drink at least 8 cups (or 64 ounces) of liquids per
Eat at least three servings of
iron-rich foods per
day to ensure you are getting 30 mg. of iron in your daily diet.
Choose at least one source of
Vitamin C every day.
Choose at least one source of folic acid every day.
Choose at least one source of Vitamin A every other
Eat three small meals and two or three snacks at
regular times every day. Do not skip meals or snacks.
Avoid alcoholic beverages during pregnancy. Alcohol
has been linked to premature delivery and low birth weight babies.
Limit caffeine to no more than 300 mg. per day
DO NOT DIET or try to lose weight during pregnancy.
Eat a variety of foods to get all the nutrients you
Regular physical activity is
sometimes used to keep blood sugar levels lower because contracting
muscles help stimulate glucose transport. In the
absence of either medical or obstetrical
prescription can be an alternative or adjunct therapy for women who have
gestational diabetes. Non-weight-bearing exercises such as stationary
swimming, and arm exercises, may be most suitable for these patients, to improve
and maintain glucose homeostasis. Walking may be another safe option. For more,
Try exercising frequently, 4 to 5 days per week, to get the “blood sugar
lowering” advantages of an exercise program. Don't omit a warm-up period of 5 to
10 minutes and a cool-down period of 5 to 10 minutes. Always stop exercising if
you feel pain, dizziness, shortness of breath, faintness, palpitations, back or
pelvic pain, or experience vaginal bleeding. Also, avoid vigorous exercise in
hot, humid weather or if you have a fever. It is important to prevent
dehydration during exercise, especially during pregnancy. The American College
of Obstetricians and Gynecologists (ACOG) recommends drinking fluids prior to
and after exercise, and if necessary, during the activity to prevent
dehydration. The maternal heart rate not exceed 140 beats per minute. Along with
the exercise program, women with gestational diabetes should follow a daily
balanced American Diabetes Association diet of 30 kcal/kg ideal body weight.
Because both insulin and exercise lower blood sugar levels, the combination
can result in hypoglycemia or low blood sugar. Therefore, when exercising, take
along sugar in the form of hard, sugar-sweetened candies just in case your blood
sugar becomes too low. If on insulin, you should always carry some form of sugar
for potential episodes of hypoglycemia.
When diet and exercise do not keep
blood glucose levels within an acceptable range, a patient may need to take
regular shots of insulin. Self-monitoring of blood glucose is required for
effective treatment with insulin. Patients are often asked to regularly measure
their blood sugar. This is done by poking a finger with a needle called a
lancet, putting a drop of blood on a special type of paper, and feeding the
paper into a meter which analyzes and reports the blood sugar level.
There is no known way to actually prevent diabetes, particularly since
gestational diabetes is due to the effects of normal hormones of pregnancy.
However, the effects of insulin resistance can be best handled through careful
attention to diet, avoiding becoming overweight throughout life, and
participating in reasonable exercise.
National Institute of Diabetes,
and Digestive and Kidney
Northwestern University Feinberg
School of Medicine
of Diabetes and Pregnancy Study
Groups Recommendations on the
Diagnosis and Classification of
Hyperglycemia in Pregnancy. Diabetes Care. March 3,
2010. Pages 675-682.
Dated 02 November 2012