Medical experts haven't agreed on a single set of screening guidelines for gestational diabetes. Some question whether gestational diabetes screening is needed if you're younger than 25 and have no risk factors. Others say that screening all pregnant women is the best way to identify all cases of gestational diabetes.
When to screen
Your doctor will likely evaluate your risk factors for gestational diabetes early in your pregnancy.
If you're at high risk of gestational diabetes — for example, your body mass index (BMI) before pregnancy was 30 or higher or you have a mother, father, sibling or child with diabetes — your doctor may test for diabetes at your first prenatal visit.
If you're at average risk of gestational diabetes, you'll likely have a screening test during your second trimester — between 24 and 28 weeks of pregnancy.
Routine screening for gestational diabetes
Initial glucose challenge test. You'll drink a syrupy glucose solution. One hour later, you'll have a blood test to measure your blood sugar level. A blood sugar level below 130 to 140 milligrams per deciliter (mg/dL), or 7.2 to 7.8 millimoles per liter (mmol/L), is usually considered normal on a glucose challenge test, although this may vary by clinic or lab.
If your blood sugar level is higher than normal, it only means you have a higher risk of gestational diabetes. You'll need a glucose tolerance test to determine if you have the condition.
- Follow-up glucose tolerance testing. You'll fast overnight, then have your blood sugar level measured. Then you'll drink another sweet solution — this one containing a higher concentration of glucose — and your blood sugar level will be checked every hour for three hours. If at least two of the blood sugar readings are higher than normal, you'll be diagnosed with gestational diabetes.
If you're diagnosed with gestational diabetes
Your doctor will likely recommend frequent checkups, especially during your last three months of pregnancy. During these exams, your doctor will monitor your blood sugar. Your doctor may also ask you to monitor your own blood sugar daily as part of your treatment plan.
If you're having trouble controlling your blood sugar, you may need to take insulin. If you have other pregnancy complications, you may need additional tests to evaluate your baby's health. These tests assess the function of the placenta, the organ that delivers oxygen and nutrients to your baby by connecting the baby's blood supply to yours.
If your gestational diabetes is difficult to control, it may affect the placenta and endanger the delivery of oxygen and nutrients to the baby.
Your doctor will also conduct tests to monitor your baby's well-being during your pregnancy.
Blood sugar testing after you give birth
Your doctor will check your blood sugar after delivery and again in six to 12 weeks to make sure that your level has returned to normal. If your tests are normal — and most are — you'll need to have your diabetes risk assessed at least every three years.
If future tests indicate diabetes or prediabetes — a condition in which your blood sugar is higher than normal, but not high enough to be considered diabetes — talk with your doctor about increasing your prevention efforts or starting a diabetes management plan.
It's essential to monitor and control your blood sugar to keep your baby healthy and avoid complications during pregnancy and delivery. You'll also want to keep a close eye on your future blood sugar levels. Your treatment strategies may include:
Monitoring your blood sugar. While you're pregnant, your health care team may ask you to check your blood sugar four to five times a day — first thing in the morning and after meals — to make sure your level stays within a healthy range. This may sound inconvenient and difficult, but it'll get easier with practice.
To test your blood sugar, you draw a drop of blood from your finger using a small needle (lancet), then place the blood on a test strip inserted into a blood glucose meter — a device that measures and displays your blood sugar level.
Your health care team will monitor and manage your blood sugar during labor and delivery. If your blood sugar rises, your baby's pancreas may release high levels of insulin — which can cause low blood sugar in your baby right after birth.
Follow-up blood sugar checks are also important. Having gestational diabetes increases your risk of developing type 2 diabetes later in life. Work with your health care team to keep an eye on your levels. Maintaining health-promoting lifestyle habits, such as a healthy diet and regular exercise, can help reduce your risk.
Healthy diet. Eating the right kinds of food in healthy portions is one of the best ways to control your blood sugar and prevent too much weight gain, which can put you at higher risk of complications. Doctors don't advise losing weight during pregnancy — your body is working hard to support your growing baby. But your doctor can help you set weight gain goals based on your weight before pregnancy.
A healthy diet focuses on fruits, vegetables and whole grains — foods that are high in nutrition and fiber and low in fat and calories — and limits highly refined carbohydrates, including sweets. No single diet is right for every woman. You may want to consult a registered dietitian or a diabetes educator to create a meal plan based on your current weight, pregnancy weight gain goals, blood sugar level, exercise habits, food preferences and budget.
Exercise. Regular physical activity plays a key role in every woman's wellness plan before, during and after pregnancy. Exercise lowers your blood sugar by stimulating your body to move glucose into your cells, where it's used for energy. Exercise also increases your cells' sensitivity to insulin, which means your body will need to produce less insulin to transport sugar.
As an added bonus, regular exercise can help relieve some common discomforts of pregnancy, including back pain, muscle cramps, swelling, constipation and trouble sleeping. Exercise can also help get you in shape for the hard work of labor and delivery.
With your doctor's OK, aim for moderately vigorous exercise on most days of the week. If you haven't been active for a while, start slowly and build up gradually. Walking, cycling and swimming are good choices during pregnancy. Everyday activities such as housework and gardening also count.
- Medication. If diet and exercise aren't enough, you may need insulin injections to lower your blood sugar. Between 10 and 20 percent of women with gestational diabetes need insulin to reach their blood sugar goals. Some doctors prescribe an oral blood sugar control medication, while others believe more research is needed to confirm that oral drugs are as safe and as effective as injectable insulin to control gestational diabetes.
- Close monitoring of your baby. An important part of your treatment plan is close observation of your baby. Your doctor may monitor your baby's growth and development with repeated ultrasounds or other tests. If you don't go into labor by your due date — or sometimes earlier — your doctor may induce labor. Delivering after your due date may increase the risk of complications for you and your baby.
Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this disease.
Coping and support
It's stressful to know you have a condition that can affect your unborn baby's health. But the steps that will help control your blood sugar level — such as eating healthy foods and exercising regularly — can help relieve stress and nourish your baby and help prevent type 2 diabetes in the future. That makes exercise and good nutrition powerful tools for a healthy pregnancy as well as a healthy life — for you and your baby.
You'll probably feel better if you learn as much as you can about gestational diabetes. Talk to your health care team. Read books and articles about gestational diabetes. Join a support group for women with gestational diabetes. The more you know, the more in control you'll feel.
Preparing for your appointment
In most circumstances, you'll learn you have gestational diabetes as the result of routine screening during your pregnancy. If your blood sugar tests high, you'll likely be asked to come in for an appointment promptly. You'll also have more-frequent regular prenatal appointments to monitor the course of your pregnancy.
Here's some information to help you get ready for your appointment and know what to expect from your doctor.
What you can do
- Be aware of pre-appointment restrictions. When you make your appointment, ask if you need to fast for bloodwork or do anything else to prepare for diagnostic tests.
- Write down symptoms you're having, including those that may seem unrelated to gestational diabetes. You may not have noticeable symptoms, but it's good to keep a log of anything unusual you notice.
- Write down key personal information, including major stresses or recent life changes.
- Make a list of all medications, including over-the-counter drugs and vitamins or supplements you're taking.
- Take a family member or friend along, if possible. Someone who accompanies you may remember something that you missed or forgot.
Questions to ask your doctor
Make a list of questions to help make the most of your time with your doctor. For gestational diabetes, some basic questions to ask your doctor include:
- What can I do to help control my condition?
- Can you recommend a dietitian or diabetes educator who can help me plan meals, an exercise program, and coping strategies?
- What will determine whether I need medication to control my blood sugar?
- What symptoms should prompt me to seek medical attention?
- Are there brochures or other printed materials I can take? What websites do you recommend?
Don't hesitate to ask other questions.
What to expect from your doctor
Your doctor is also likely to have questions for you, especially if you're seeing him or her for the first time. Your doctor may ask:
- Have you experienced increased thirst or excessive urination? If so, when did these symptoms start? How often do you have them?
- Have you noticed other unusual symptoms?
- Do you have a parent or sibling who's ever been diagnosed with diabetes?
- Have you been pregnant before? Did you have gestational diabetes during your previous pregnancies?
- Did you have other problems in earlier pregnancies?
- If you have other children, how much did each weigh at birth?
- Have you gained or lost a lot of weight at any time in your life?
What you can do in the meantime
You can take steps to control gestational diabetes as soon as you're diagnosed. If your doctor recommends further evaluation, make your follow-up appointments as soon as possible. Every week counts for you and your baby.
Follow your doctor's advice, and take good care of yourself. Eat healthy foods, exercise and learn as much as you can about gestational diabetes.