Pregnancy and Gestational Diabetes

Last Editorial Review: 5/15/2012

What is Gestational Diabetes?

Gestational diabetes is a condition characterized by high blood sugar (glucose) levels that is first recognized during pregnancy. The condition occurs in approximately 4% of all pregnancies.

What Causes Gestational Diabetes?

Almost all women have some degree of impaired glucose intolerance as a result of hormonal changes that occur during pregnancy. That means that their blood sugar may be higher than normal, but not high enough to have diabetes. During the later part of pregnancy (the third trimester), these hormonal changes place pregnant woman at risk for gestational diabetes.

During pregnancy, increased levels of certain hormones made in the placenta (the organ that connects the baby by the umbilical cord to the uterus) help shift nutrients from the mother to the developing fetus. Other hormones are produced by the placenta to help prevent the mother from developing low blood sugar. They work by resisting the actions of insulin.

Over the course of the pregnancy, these hormones lead to progressive impaired glucose intolerance (higher blood sugar levels). To try to decrease blood sugar levels, the body makes more insulin to get glucose into cells to be used for energy.

Usually the mother's pancreas is able to produce more insulin (about three times the normal amount) to overcome the effect of the pregnancy hormones on blood sugar levels. If, however, the pancreas cannot produce enough insulin to overcome the effect of the increased hormones during pregnancy, blood sugar levels will rise, resulting in gestational diabetes.

What Are the Complications of Gestational Diabetes?

Diabetes can affect the developing fetus throughout the pregnancy. In early pregnancy, a mother's diabetes can result in birth defects and an increased rate of miscarriage. Many of the birth defects that occur affect major organs such as the brain and heart.

During the second and third trimester, a mother's diabetes can lead to over-nutrition and excess growth of the baby. Having a large baby increases risks during labor and delivery. For example, large babies often require caesarean deliveries and if he or she is delivered vaginally, they are at increased risk for trauma to their shoulder.

In addition, when fetal over-nutrition occurs and hyperinsulinemia results, the baby's blood sugar can drop very low after birth, since it won't be receiving the high blood sugar from the mother.

However, with proper treatment, you can deliver a healthy baby despite having diabetes.

Who Is At Risk for Gestational Diabetes?

The following factors increase the risk of developing gestational diabetes during pregnancy:

  • Being overweight prior to becoming pregnant (if you are 20% or more over your ideal body weight).
  • Being a member of a high risk ethnic group (Hispanic, Black, Native American, or Asian).
  • Having sugar in your urine.
  • Impaired glucose tolerance or impaired fasting glucose (blood sugar levels are high, but not high enough to be diabetes).
  • Family history of diabetes (if your parents or siblings have diabetes).
  • Previously giving birth to a baby over 9 pounds.
  • Previously giving birth to a stillborn baby.
  • Having gestational diabetes with a previous pregnancy.
  • Having too much amniotic fluid (a condition called polyhydramnios).

Many women who develop gestational diabetes have no known risk factors.

How Is Gestational Diabetes Diagnosed?

High risk women should be screened for gestational diabetes as early as possible during their pregnancies. All other women will be screened between the 24th and 28th week of pregnancy.

To screen for gestational diabetes, you will take a test called the oral glucose tolerance test. This test involves quickly drinking a sweetened liquid, which contains 50g of sugar. The body absorbs this sugar rapidly, causing blood sugar levels to rise within 30-60 minutes. A blood sample will be taken from a vein in your arm 1 hour after drinking the solution. The blood test measures how the sugar solution was metabolized (processed by the body).

A blood sugar level greater than or equal to 140mg/dL is recognized as abnormal. If your results are abnormal based on the oral glucose tolerance test, another test will be given after fasting for several hours.

In women at high risk of developing gestational diabetes, a normal screening test result is followed up with another screening test at 24-28 weeks for confirmation of the diagnosis.

How Is Gestational Diabetes Managed?

Gestational diabetes is managed by:

  • Monitoring blood sugar levels four times per day - before breakfast and 2 hours after meals. Monitoring blood sugar before all meals may also become necessary.)
  • Monitoring urine for ketones, an acid that indicates your diabetes is not under control.
  • Following specific dietary guidelines as instructed by your doctor. You'll be asked to distribute your calories evenly throughout the day. the day.
  • Exercising after obtaining your health care provider's permission.
  • Monitoring your weight gain.
  • Taking insulin, if necessary. Insulin is currently the only diabetes medication used during pregnancy.
  • Controlling high blood pressure.

How Do I Monitor My Blood Sugar Levels?

Testing your blood sugar at certain times of the day will help determine if your exercise and eating patterns are keeping your blood sugar levels in control, or if you need extra insulin to protect your developing baby. Your health care provider will ask you to maintain a daily food record and ask you to record your home sugar levels.

Testing your blood sugar involves pricking your finger with a lancet device (a small, sharp needle), putting a drop of blood on a test strip, using a blood sugar meter to display your results, recording the results in a log book, and then disposing the lancet and strips properly (in a "sharps" container or a hard plastic container, such as a laundry detergent bottle).

Bring your blood sugar readings with you to your medical appointments so your health care provider can evaluate how well your blood sugar levels are controlled and determine if changes need to be made to your treatment plan.

Your health care provider will show you how to use a glucose meter. He or she can also tell you where to get a meter. You may be able to borrow it from your hospital, as many hospitals have loaner meter programs for women with gestational diabetes.

The goal of monitoring is to keep your blood sugar as close to normal as possible. The ranges include:

Monitoring Blood Glucose
Time of Test Target Blood Sugar Reading
Before breakfast plasma below 105; whole blood below 95
2 Hours After Meals plasma below 130; whole blood below 120

Insulin is started if above levels are not maintained.

Do I Need to Take Insulin for Gestational Diabetes?

Based on your blood sugar monitoring results, your health care provider will tell you if you need to take insulin in the form of injections during pregnancy. Insulin is a hormone that controls blood sugar. If insulin is prescribed for you, you may be taught how to perform the insulin injection procedure.

As your pregnancy progresses, the placenta will make more pregnancy hormones and larger doses of insulin may be needed to control your blood sugar. Your health care provider will adjust your insulin dosage based on your blood sugar log.

When using insulin, a "low blood glucose reaction," or hypoglycemia, can occur if you do not eat enough food, skip a meal, do not eat at the right time of day, or if you exercise more than usual.

Symptoms of hypoglycemia include:

Hypoglycemia is a serious problem that needs to be treated right away. If you think you are having a low blood sugar reaction, check your blood sugar. If your blood sugar is less than 60 mg/dL (milligrams per deciliter), eat a sugar-containing food, such as 1/2 cup of orange or apple juice; 1 cup of skim milk; 4-6 pieces of hard candy (not sugar-free); 1/2 cup regular soft drink; or 1 tablespoon of honey, brown sugar, or corn syrup. Fifteen minutes after eating one of the foods listed above, check your blood sugar. If it is still less than 60 mg/dL, eat another one of the food choices above. If it is more than 45 minutes until your next meal, eat a bread and protein source to prevent another reaction.


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Record all low blood sugar reactions in your log book, including the date, time of day the reaction occurred and how you treated it.

How Will My Diet Change With Gestational Diabetes?

If you have gestational diabetes, follow these diet tips:

  • Eat three small meals and two or three snacks at regular times every day. Do not skip meals or snacks. Carbohydrates should be 40%-45% of the total calories with breakfast and a bedtime snack containing 15-30 grams of carbohydrates.
  • If you have morning sickness, eat 1-2 servings of crackers, cereal, or pretzels before getting out of bed. Eat small, frequent meals throughout the day and avoid fatty, fried, and greasy foods. If you take insulin and have morning sickness, make sure you know how to treat low blood sugar.
  • Choose foods high in fiber such as whole-grain breads, cereals, pasta, rice, fruits, and vegetables. All pregnant women should eat 20-35 grams of fiber a day.
  • Fats should be less than 40% of calories with less than 10% consumed being from saturated fats.
  • Drink at least 8 cups (or 64 ounces) of liquids per day.
  • Make sure you are getting enough vitamins and minerals in your daily diet. Ask your health care provider about taking a prenatal vitamin and mineral supplement to meet the nutritional needs of your pregnancy.

How Much Exercise Is Safe for Gestational Diabetes?

Regular exercise during pregnancy can improve your posture and decrease some common discomforts such as backaches and fatigue. Being fit during pregnancy means safe, mild to moderate exercise at least three times a week. But, regardless of gestational diabetes, every pregnant woman should consult with her health care provider before beginning an exercise program. He or she can give you personal exercise guidelines, based on your medical history.

Since both insulin and exercise lower blood sugar, you should follow these additional exercise guidelines to avoid a low blood glucose reaction:

  • Always carry some form of sugar with you when exercising, such as glucose tablets or hard candy.
  • Eat one serving of fruit or the equivalent of 15 grams of carbohydrate for most activities lasting 30 minutes. If you exercise right after a meal, eat this snack after exercise. If you exercise 2 hours or more after a meal, eat the snack before exercise.

Pregnancy Weight Gain

The recommended amount of weight gain during pregnancy depends on your pre-pregnancy weight, whether there is more than one fetus, and the trimester. Typically more weight gain is expected during the second and third trimester and recommended intakes of calories should increase at that time.

Gaining the right amount of weight during pregnancy by eating a healthy, balanced diet is a good sign that your baby is getting all the nutrients he or she needs and is growing at a healthy rate.

It is not necessary to "eat for two" during pregnancy. It's true that you need extra calories from nutrient-rich foods to help your baby grow, but you generally need to consume only 200 to 300 more calories per day than you did before you became pregnant to meet the needs of your growing baby.

Ask your health care provider how much weight you should gain during pregnancy. A woman of average weight before pregnancy can expect to gain 25 to 35 pounds during pregnancy. You may need to gain more or less weight, depending on what your doctor recommends.

In general, you should gain about 2-4 pounds during your first 3 months of pregnancy and 1 pound a week for the remainder of your pregnancy.

Where the weight goes
Baby 8 pounds
Placenta 2-3 pounds
Breast tissue 2-3 pounds
Blood supply 4 pounds
Fat stores for delivery and breastfeeding 5-9 pounds
Uterus increase 2-5 pounds
TOTAL 25 to 35 pounds

What Happens to My Baby After Delivery?

Your baby's blood sugar level will be tested immediately after birth. If the blood sugar is low, he or she will be given sugar water to drink or by an intravenous tube in the vein. Your baby may be sent to a special care nursery for observation during the first few hours after birth to make sure he or she doesn't have a low blood glucose reaction.

If you had gestational diabetes, there is an increased risk that your newborn will develop jaundice. Jaundice is a yellow discoloration of the skin that occurs when bilirubin is present in the baby's blood. Bilirubin is a pigment that causes jaundice and is released when extra red blood cells build up in the blood and can't be processed fast enough. Jaundice goes away rapidly with treatment that often involves exposing your baby to special lights to get rid of the pigment.

Will Gestational Diabetes Cause the Baby to Have Diabetes?

Gestational diabetes does increase the risk that your child will have diabetes in the future.

Will I Still Have Diabetes After I Deliver My Baby?

Usually with gestational diabetes, blood sugar levels return to normal about 6 weeks after childbirth because the placenta, which was producing the extra hormones that caused insulin resistance, is gone. Your doctor will check your blood sugar levels after your baby is born to make sure your blood sugar level has returned to normal. Some doctors recommend an oral glucose tolerance test 6-8 weeks after delivery to check for diabetes.

You should also be screened for diabetes in the future. Women who have had gestational diabetes have a 60% increased risk of developing type 2 diabetes later-in-life. By maintaining an ideal body weight, following a healthy diet, and exercising, you will be able to reduce your risk of developing type 2 diabetes.

In addition, women who have gestational diabetes during one pregnancy have a 40%-50% chance of developing diabetes in the next pregnancy. If you had gestational diabetes during one pregnancy and are planning to get pregnant again, talk to your health care provider first so you can make the necessary lifestyle changes before your next pregnancy.

WebMD Medical Reference

Health Solutions From Our Sponsors

American Diabetes Association: "Gestational Diabetes."
Agency for Healthcare Research and Quality: "Gestational Diabetes: A Guide for Pregnant Women."
American College of Nurse Midwives: "Gestational Diabetes."

Reviewed by Michael Dansinger, MD on May 15, 2012
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