Gestational diabetes complicates about 3%-5% of all pregnancies-affecting approximately 200,000 women each year in the US. It is caused by hormonal changes during pregnancy that make the body more insulin intolerable. If left untreated, gestational diabetes can cause serious complications for both mother and child. It typically develops around 24 weeks and goes away after giving birth, though women with gestational diabetes are at a higher risk for developing type 2 diabetes. In most cases, symptoms of gestational diabetes disappear immediately after pregnancy – only 5-10% of women with gestational diabetes remain diabetic (typically type 2 diabetics). However, gestational diabetes does raise the risk of developing diabetes in later years. Women who have had gestational diabetes have a 35% to 60% chance of developing diabetes in the next 10–20 years. Recently implemented diagnostic criteria for gestational diabetes will increase the proportion of women diagnosed with gestational diabetes. Using these new diagnostic criteria, an international, multicenter study of gestational diabetes found that gestational diabetes actually affects 18% of pregnancies.
What Is Gestational Diabetes
What Causes Gestational Diabetes
Lowered insulin levels are the underlying cause of all diabetes. Insulin is produced by the islet cells of the pancreas, which then circulate it to your body via the blood stream. In the presence of insulin, glucose (sugar) is able to transfer from the blood stream into the body cells, lowering the blood glucose level and providing the body’s cells with fuel for energy. In diabetic patients, there are several factors that can interfere with this process.
In gestational diabetes, the normal pregnancy hormones produced by the placenta to prevent low blood sugar (i.e. cortisol and estrogen) lower the body’s insulin levels to a potentially dangerous diabetic level. Like the other types of diabetes, the exact cause of gestational diabetes is unknown, however researchers have found that obese women and those with a family history of diabetes are at a higher risk.
The exact cause of gestational diabetes is unknown. But these factors may contribute to the condition:
- Hormones needed for the baby’s growth interfere with insulin
- Excess maternal weight increases insulin resistance
- Insulin resistance prevents the body from effectively using insulin
Risk Factors For Gestational Diabetes
It is possible to develop gestational diabetes with or without the risk factors listed below. However, the more risk factors you have, the greater your likelihood of developing gestational diabetes. If you have a number of risk factors, ask your doctor what you can do to reduce your risk.
Risk factors for gestational diabetes include:
- Obesity or Being Overweight. Studies found that women with a body mass index (BMI) of 25.0 to 29.9 (classified as overweight) are at an increased risk of gestational diabetes. If your BMI is over 30, you may be at a great risk.
- Gestational Diabetes in a Previous Pregnancy. If you had gestational diabetes with a previous pregnancy, this puts you at risk for developing the condition again, depending on your weight during the first trimester.
- Age. Gestational diabetes is more common in women who are older than 35.
- Family History of Diabetes. If you have a first-degree relative (parents, siblings) with diabetes, your risk of gestational diabetes is increased.
- Race. You may be at an increased risk of developing gestational diabetes if you are:
- Hispanic American
- African American
- Native American
- Asian American
- Indigenous Australian
- Pacific Islander
- Previous Delivery of a Large Baby. Fetal macrosomia is defined as having a baby with a birth weight greater than the 90th percentile for gestational age and sex. If you delivered a baby with fetal macrosomia, you are at increased risk of gestational diabetes in future pregnancies.
- Other Risk Factors:
- Previous history of glucose intolerance
- Previous history of Polycystic Ovary Syndrome
- Previous history of Type 1 Diabetes or Type 2 Diabetes
- Rapid weight gain during pregnancy
- Risk factors related to childbirth:
- Previous stillbirth
- Having a child with a birth defect
- Too much amniotic fluid surrounding a baby during pregnancy
Diagnosing Gestational Diabetes
Your doctor should assess your risk for gestational diabetes at your first prenatal visit. If you have a fasting blood sugar greater than 126 milligrams per deciliter (mg/dL) [7.0 mmol/L], or a random blood sugar greater than 200 mg/dL (11.1 mmol/L), that is confirmed on another day, you meet the criteria for the diagnosis of Type 2 Diabetes and you do not need to be screened.
If you are at high risk of developing gestational diabetes-very overweight, prior history of gestational diabetes, glucose in your urine, or a strong family history of diabetes-your doctor may recommend that you undergo glucose testing as soon as possible. If your initial test is not positive you should be retested between 24 and 28 weeks of gestation.
Women who are of average risk should be given the 50-gram screening test between 24-28 weeks of gestation.
Newer guidelines do not require glucose testing for low-risk women, but to be low risk you must meet all of the following criteria: less than 25 years of age, normal weight before and during pregnancy, not a member of an ethnic group with a high risk of diabetes (Asian American, African American, Hispanic American, native American, or Pacific Islander), no known diabetes in any siblings or parents, no history of abnormal glucose tolerance, no glucose in urine, and no history of poor obstetric outcomes.
The 50-gram test is used to screen for gestational diabetes, while the 3-hour glucose tolerance test is used to diagnose gestational diabetes.
- 50-gram glucose screening test -You do not need to fast before this test. You are given a drink that contains 50 grams of glucose. One hour later, your blood is drawn to test your sugar level. If your blood sugar level is less than 130 mg/dL (7.2 mmol/L) at the one-hour mark, the likelihood that you have gestational diabetes is low and you will not require further testing. If your blood sugar level is greater than 130 mg/dL (7.2 mmol/L), the test is considered abnormal or positive. Your chance of having gestational diabetes mellitus is 90%. You will need to take the 3-hour oral glucose tolerance test to confirm the diagnosis. Not all women that have an abnormal or positive 50-gram glucose test have gestational diabetes.
- 100-gram diagnostic glucose tolerance test -Prior to this test, you will need to follow some special dietary restrictions.
- Three days before the test: Eat a diet that contains at least 150 grams of carbohydrates a day.
- For 10 to 14 hours before the test: Do not eat or drink anything, except water
The test is usually done in the morning in your doctor’s office. First, a blood sample is drawn to measure your fasting blood glucose level. Next, you will drink a glucose drink that contains 100 grams of glucose. The drink is very sweet; some people even feel a bit nauseated after drinking it. Blood samples are drawn every hour for three hours after you finish the drink.
The diagnostic values used by the American Diabetes Association are as follows:
|Time||Blood glucose values|
|Fasting||95 mg/dL (5.3 mmol/L)|
|1 hour||180 mg/dL (10 mmol/L)|
|2 hours||155 mg/dL (8.6 mmol/L)|
|3 hours||140 mg/dL (7.8 mmol/L)|
If two or more of your blood sugar levels are higher than the diagnostic blood glucose values, you have gestational diabetes. Once you have been diagnosed with gestational diabetes, your doctor will work with you to develop an appropriate treatment plan.
In addition to the above screening tests, additional tests may include:
- Glycosylated hemoglobin (HbA1c)-a blood test which reflects the cumulative changes in your blood surgar over the last three months
- Urine tests-protein (24 hour collection), ketones
- Thyroid function tests: TSH and free thyroxine test
- Tests to monitor the fetus- ultrasound (usually done at 30-32 and 36-38 weeks), counting of fetal movement, amniotic fluid analyses
Symptoms of Gestational Diabetes
Gestational Diabetes usually does not cause symptoms distinguishable from those that commonly occur in pregnancy. If symptoms do occur, they may be similar to those in nongestational diabetes. These may include:
- Increased urination (polyuria). When glucose accumulates in the blood, it pulls water out of the body’s tissues and into the blood. The kidneys turn this extra water into urine and excrete it. This increases your urine output.
- Increased thirst (polydipsia). The increase in urine output causes your body to become Dehydration. This makes you thirsty.
- Increased hunger. Your body’s cells are not getting enough glucose, which means your cells cannot get enough food. This causes you to feel hungry.
- Recurring urinary tract infection or vaginal yeast infection. When glucose builds up in the blood, it can affect the functioning of your white blood cells. This may cause you to have urinary tract infections or vaginal yeast infections more often.
- Weight loss. Despite the increase in appetite, you may lose weight. This is because the cells cannot get enough glucose to use for energy so they begin to break down the body’s stores of fat in order to produce energy.
- Fatigue. Because your cells are not getting glucose, they cannot get enough energy. This can make you feel tired.
Gestational diabetes typically goes away after giving birth, though mothers who have had gestational diabetes are at a higher risk of developing type 2 diabetes.
Living With Gestational Diabetes
If you are diagnosed with gestational diabetes, there are a number of things that you can do to help.
Eat a healthy diet. Try spreading out your daily food intake into smaller meals and snacks, which will help you manage your blood sugar levels and provide the best nutrition for you and your growing baby.
Gain a healthy amount of weight for your pregnancy—take care not to gain too much. The amount of weight you gain will be in part based on your weight prior to pregnancy. Talk to your midwife or doctor about what a healthy amount of weight gain would be for you.
Get physical. One of the best things you can do is move around. Regular physical activity can help keep blood sugar levels under control, and also has the added benefits of:
- Boosting energy
- Reducing stress
- Better sleep
- Gets your body primed to get in shape faster post-childbirth
- Helps reduce pregnancy aches and pains
The purpose of screening is early diagnosis and treatment. Screening tests are usually administered to people without current symptoms, but who may be at high risk for certain diseases or conditions.
Your doctor should assess your risk for gestational diabetes at your first prenatal visit. You meet the criteria for the diagnosis of Type 2 Diabetes and you do not need to be screened if you have:
- A fasting blood sugar greater than 126 milligrams per deciliter (mg/dL) [7 mmol/L], or
- A random blood sugar greater than 200 mg/dL (11.1 mmol/L) that is confirmed on another day
If you are at high risk of developing gestational diabetes, your doctor may recommend that you undergo glucose tolerance testing as soon as possible. If your initial test is not positive, you should be retested between 24 and 28 weeks of gestation.
If you are at average risk, then you should be given the 50-gram screening test between 24-28 weeks of gestation.
Newer guidelines do not require glucose testing for low-risk women. But, to be low risk you must meet all of the following criteria:
- Less than 35 years of age
- Normal weight before pregnancy
- Not a member of an ethnic group with a high risk of diabetes (Hispanic American, African American, Native American, Asian American, Indigenous Australian, Pacific Islander)
- No history of diabetes in parents or siblings
- No history of abnormal glucose tolerance
- No glucose in urine
- No history of poor outcomes of pregnancy
For the 50-gram glucose screening test, you do not need to fast. You are given a drink that contains 50 grams of glucose. One hour later, your blood sugar level is tested.
- If your blood sugar level is less than 130 mg/dL (7.2 mmol/L) at the one-hour mark-The likelihood that you have gestational diabetes is low. You do not require further testing.
- If your blood sugar level is greater than 130 mg/dL (7.2 mmol/L)-The test is considered abnormal or positive. Your chance of having gestational diabetes is 90%. You will need to take the three-hour oral glucose tolerance test to confirm the diagnosis. Not all women that have an abnormal or positive 50-gram glucose test have gestational diabetes.
Here are some ways to reduce your risk of gestational diabetes:
- Maintain a normal weight gain during pregnancy.
- Eat a healthy diet.
- Exercise regularly.
Maintain a Normal Weight Gain During Pregnancy
The National Academy of Science’s Institute of Medicine makes the following recommendations regarding weight gain during pregnancy:
|Weight classification before pregnancy*||Institute of Medicine recommended gestational weight gain|
|Underweight (BMI 19.7 and under)||28 to 40 lb|
|Normal (BMI 19.8-24.9)||25 to 35 lb|
|Overweight (BMI 25-29.9)||15 to 25 lb|
|Obese (BMI 30 or greater)||15 to 25 lb|
*These values are based on body mass index (BMI)-the ratio of your weight in kilograms to your height in meters squared. Recognize that these values are for Caucasians, which may not apply to Asians who have smaller body frames and different percentage of body fat.
Besides increasing your risk for gestational diabetes, excessive weight gain during pregnancy is also a risk factor for overweight post-pregnancy. It should be noted that the subject of recommended pregnancy weight gain remains somewhat controversial and that some feel that the above guidelines are too high. Talk with your doctor about what range of weight gain is right for you.
Eat a Healthful Diet
Even before pregnancy begins, nutrition is a primary factor in the health of the mother and the baby. Besides lowering your risk of Gestational Diabetes, eating a healthy diet lowers your and your baby’s risk of serious complications during and after pregnancy. A healthy diet is one that is low in saturated fat and rich in fruits, vegetables, and whole grains.
The US Department of Agriculture’s MyPyramid website has dietary guidelines for pregnant and nursing women. The interactive site allows you to create a personalized food plan.
Participating in a regular exercise program can lower your risk of developing gestational diabetes by helping you maintain a healthy weight. But, it is very important that you discuss exercise with your doctor before you begin.
Choose exercises that do not require your body to bear any extra weight. Good examples are:
- Stationary cycling
- Low-impact aerobics
When you exercising, be sure to stay hydrated. Drink plenty of fluids, even if you are not thirsty. If your body temperature goes up too high, it can be dangerous for your baby.
Avoid contact sports or vigorous sports. Also, avoid any exercises that increase your risk of falls or injury.
Medication And Treatment
The treatment and management of gestational diabetes involves lifestyle modifications (such as eating a healthful diet and beginning an exercise program), frequent daily blood sugar testing, and possibly insulin.
Gestational diabetes treatment aims to control your blood sugar level, thereby reducing possible complications to you and your baby. According to the Mayo Clinic, between 10 and 20 percent of women with gestational diabetes need insulin. In addition, some physicians prescribe an oral blood sugar control medication (see the list above). However, other doctors feel that not enough research has been done to confirm that oral drugs are as safe and as effective as injectable insulin for pregnant women with gestational diabetes. If your doctor prescribes an oral medication, you may want to consider getting a second opinion. Many people with diabetes use combinations of medications and insulin to better control and manage their condition. Your physician and the other members of your care team will help determine what is best for you. n.
Complementary and Alternative Treatment
Aside from lifestyle modifications, which can be very positively impacting, there is no evidence that herbal supplements can help to control gestational diabetes or its complications. As well, one needs to be very careful with any type of herb or medication when pregnant. Please talk to your health care provider before taking any type of supplement, herb, or medicine.
When To Contact A Doctor
If you suspect that you have diabetes or you find that you are experiencing one or more of the symptoms of diabetes, you should talk to your doctor. He or she will be able to run the proper diagnostic tests and determine whether or not diabetes is causing your symptoms.
If you have already been diagnosed with diabetes, call your doctor immediately if:
- You are sick and cannot control your blood sugar.
- You have been vomiting or have had diarrhea for more than six hours.
- You have a blood sugar level that stays higher or lower than the range your doctor has set for you.
- You have symptoms of low blood sugar which include:
- Shakiness and weakness
- Extreme hunger and slight nausea
- Dizziness and headache
- Blurred vision
Call 911 emergency services right away if you have symptoms of diabetic ketoacidosis (DKA) a life-threatening condition that develops when the body is not getting enough insulin. These include:
- Blurred vision
- Trouble staying awake or trouble being woken up
- Fast, deep breathing
- Breath that smells fruity
- Belly pain, not feeling hungry, and vomiting
Questions For Your Doctor
If you suspect you have gestational diabetes, speak to your midwife or OB/Gyn immediately.
Questions For A Doctor
You have a unique medical history. Therefore, it is essential to talk with your doctor about your personal risk factors and/or experience with gestational diabetes. By talking openly and regularly with your doctor, you can take an active role in your care.
Here are some tips that will make it easier for you to talk to your doctor:
- Bring someone else with you. It helps to have another person hear what is said and think of questions to ask.
- Write out your questions ahead of time, so you don’t forget them.
- Write down the answers you get, and make sure you understand what you are hearing. Ask for clarification, if necessary.
- Do not be afraid to ask your questions or ask where you can find more information about what you are discussing. You have a right to know.
Specific questions to ask your midwife or doctor about gestational diabetes
- Will gestational diabetes hurt my unborn baby?
- What effect will gestational diabetes have on my unborn baby?
- Where can I find more information about gestational diabetes?
- Can you recommend a support group for women with gestational diabetes?
- Based on my medical history, lifestyle, and family background, am I at risk of gestational diabetes?
- What specific things can I do to reduce my risk of developing gestational diabetes?
- Is there a special diet?
- If so, what is it?
- Can you recommend a registered dietitian?
- Is there a special exercise program?
- If so, what is it?
- How can I get started exercising?
About Treatment Options
- What treatments are used with gestational diabetes?
- What treatment is appropriate for me? Why?
- What should I do to be ready for treatment?
- How long will my treatment last?
- What risks and side effects should I watch for?
- Will it affect my normal activities?
- What happens if I do nothing?
- What medicines are available to me?
- Are medicines safe for my unborn baby?
- What are the benefits/side effects of these medicines?
- Will these medicines interact with other medicines, over-the-counter products, or dietary or herbal supplements that I am already taking?
- Will I have to give myself shots of insulin everyday?
- Are there any alternative or complementary therapies that will help me?
About Lifestyle Changes
- What lifestyle changes can I make to treat my gestational diabetes?
- Should I follow a special diet?
- Are there any dietary changes I should make? How do I go about it?
- Can you recommend a registered dietitian?
- Should I begin an exercise program?
- What kind of exercise is best?
- How often should I exercise?
- How do I get started exercising?
- Will I have diabetes for the rest of my life?
- Will my baby have diabetes?
- What can I do to prevent this from happening in my next pregnancy?
- What can I tell my husband, children, parents, and other family members and friends about my condition?
- What is my expected prognosis?
- How often will I need checkups?