Gestational Diabetes

What is Gestational Diabetes?

During pregnancy, hormonal changes may cause impaired glucose tolerance and higher insulin needs. If the pancreas in a pregnant woman cannot keep up with the insulin needs, the blood glucose levels will rise above desired levels. Higher than normal blood glucose levels are harmful to the woman and her fetus. About 1 in 15 women develop gestational diabetes when pregnant.

How is Gestational Diabetes Diagnosed?

Most women have an oral glucose tolerance test between weeks 24-28 during pregnancy, the second trimester. A high blood glucose test earlier in the pregnancy would alert the doctor to investigate sooner. The glucose challenge screening test consists of consuming 50 grams of glucose and then testing the level of glucose in the blood before the test and one hour after consuming the glucose. The one hour blood glucose should be less than 140 mg/dL. If higher, a glucose tolerance test may be ordered. A glucose tolerance diagnostic test for gestational diabetes consists of drinking 100 grams of glucose and testing blood glucose fasting and every hour for three hours. The trends in the rise of blood glucose define the diagnosis. If two or more of these values are exceeded in the oral glucose tolerance test (OGTT)

  • Fasting: greater than 95 mg/dL
  • 1 hour: greater than 180 mg/dL
  • 2 hour: greater than 155 mg/dL
  • 3 hour: greater than 140 mg/dL

What is the Concern?

The developing baby is affected by the high blood sugars in utero. In early pregnancy, high blood sugars in the mother can cause birth defects and increase the chance of a miscarriage. During the second and third trimesters of the pregnancy, both mother and baby can gain excessive weight. A large baby is at increased risk during labor and delivery. The baby, which may have high blood glucose before birth, will have a severe drop in blood glucose at birth, and must be carefully monitored. The baby is at increased risk of jaundice just after birth, which is treated with special lights to remove the bilirubin pigment that has collected in the blood and skin. With proper treatment, a woman with gestational diabetes can have a healthy baby. Her blood glucose levels will usually return to normal after delivery. Women that have been diagnosed with Gestational Diabetes need to get retested 6-12 weeks after delivery by doing a 2 hour glucose tolerance test to evaluate glucose levels.  Women that have had gestational diabetes are at an increased risk for developing Diabetes within 5-10 years. It is important to continue visiting your doctor and staying up to date with your blood work.

Who is at Risk?

This is a list of factors that increase the risk of developing gestational diabetes for women during pregnancy:

  • Overweight prior to pregnancy (20 percent or more over ideal body weight)
  • High risk ethnic group: Hispanic, African American, Native American, Asian
  • Impaired glucose tolerance or traces of glucose in the urine
  • Family history of diabetes
  • Previously giving birth to a baby over 9 lbs. or stillborn
  • Previous pregnancy with gestational diabetes

How is Gestational Diabetes Treated?

Blood glucose goals during pregnancy are much lower than when not pregnant, before meals 60-95 and 2 hour after meals <120. To do this, the woman will need a blood glucose monitor and test her blood sugar often, minimally four times a day. Urine is also checked for ketones, which means poor control if present. There are dietary changes that are designed to limit carbohydrates, but provide adequate carbohydrate, calories and nutrients for acceptable weight gain. A registered dietitian or certified diabetes educator can provide appropriate meals plans. The woman will have exercise recommendations, and her weight gain will be closely monitored. If blood glucose levels cannot be controlled by diet, oral medication or insulin will be needed.

More on the Diet

A diet for someone with gestational diabetes is typically three small meals and two or three snacks. Meals and snacks should not be skipped. If utilizing insulin, the woman is in danger of low blood sugars also, which could cause dizziness, confusion, weakness and passing out. Carbohydrates are planned to be lower than normal, 40-45 percent of total calories. These will be distributed evenly throughout the day. High fiber foods, healthy fats and lean proteins are recommended. Drinking plenty of non-caloric fluids (64 oz.) a day and taking a prenatal vitamin are important habits.

Weight Gain

Women of average weight are expected to gain 25-35 lbs during pregnancy. Your doctor might alter these recommendations depending on the beginning pregnancy weight. The rate of weight gain is very important. During the first three months, the weight gain is 2-4 lbs., then about one pound each week the rest of the pregnancy. After delivery, a woman’s blood sugar should return to normal, but will be rechecked 6-8 weeks postpartum. Maintaining an ideal body weight, healthy diet and exercise routine, the woman can reduce her risk of developing problems with blood glucose in the future. The child will also have an increased risk of diabetes in their lifetime.

Pregnancy and Diabetes

Pregnancy presents challenges to a woman’s body, and even more so to a woman who has diabetes. With good pre-conception medical care, a female with diabetes can have a healthy pregnancy and deliver a healthy baby.

Pre-Conception Health

If you are planning on starting a family, be sure to discuss this with your diabetes healthcare team, and your gynecologist. Excellent blood sugar control three months prior to conception is critical to reduce the risk of miscarriage and birth defects. This tight blood glucose control is also as critical in the first trimester. Research indicates than an A1C within one percent of normal does not increase outcome risk, but above that the incidence of complications rises. You may choose to test more frequently (six-eight times a day) to be in good control. There are serious risks if you conceive with high blood glucose levels.

You may also want to have a thorough physical exam to assess the effects diabetes may have had on your body up until now. Pregnancy can possibly worsen these complications. Make sure to have a dilated eye exam before you become pregnant and continue to see your eye doctor during the pregnancy. If you have high blood pressure, you will need to be on specific hypertensive drugs.  ACE inhibitors, beta-blockers and diuretics are not recommended during pregnancy. You could develop high blood pressure during pregnancy, so have your pressure checked regularly. Nerve damage from diabetes may affect your extremities, or internal organs and their function, and may worsen during pregnancy. Cardiovascular disease, if present, will need to be addressed for a healthy pregnancy. You can also begin taking prenatal vitamins three-six months before you conceive; to be sure you have adequate levels of folic acid, iron, B vitamins and calcium.

Pregnancy and Prenatal Care

During the first three months of pregnancy, the fetus is developing and growing rapidly. Maintaining tight blood glucose is critical to the successful outcome. Your healthcare team will help you switch to insulin, because oral hypoglycemic agents are not approved safe for pregnancy. You will need to check your blood more frequently during this time. Before meals, your blood glucose goal should be 70-100mg/dl, and two hours after eating below 140mg/dl. You will be more susceptible to the potential of hypoglycemia and will need to know how to recognize and treat it. As you and the baby gain weight, food and medication needs will also change. Your insulin needs will increase as the baby grows. The support of your healthcare team is critical to the best outcomes.

Your dietitian can help with your increased food intake and weight gain, adjusting your carbohydrate intake and medication. You will also have certain food restrictions that all pregnant women have for food safety. Certain foods may contain listeria, a dangerous bacterium that can grow even in a cold refrigerator. Some fish have high levels of mercury, a harmful metal. Toxoplasma is a parasite found in undercooked meats and unwashed fruits and vegetables. All of these food issues could cause serious illness and death to you and your unborn baby.

While pregnant, DO NOT Eat:

  • Swordfish, tilefish, king mackerel, shark
  • Raw or uncooked meat, poultry, fish or shellfish (raw oysters, sushi, sashimi)
  • Refrigerated smoked seafood like whitefish, salmon, mackerel. Products labeled Nova-style, lox, kippered or jerky;  canned smoked seafood is allowed
  • Refrigerated pates or meat spreads
  • Hot dogs and luncheon meats, unless steaming hot
  • Soft cheeses like feta, brie, Camembert, blue-veined cheeses, queso blanco, queso freso, or panela unless the label says “pasteurized”
  • Raw or unpasteurized milk or foods that contain unpasteurized milk
  • Raw or undercooked eggs, also found in Caesar dressing, cookie dough, Hollandaise sauce and homemade custard
  • Sprouts such as bean and alfalfa
  • Unwashed fruits and vegetables

While pregnant you are allowed to eat:

  • Six ounces a week or less: tuna steaks, canned albacore or chunk white tuna, halibut, snapper
  • 12 ounces a week or less: shrimp, crab, clams, oysters, scallops, canned light tuna, salmon, mahi-mahi, pollock, catfish, or cod.

Your doctor and dietitian will monitor your weight gain during pregnancy. If you conceived at your normal weight, it is recommended you gain 25-30 lbs. If overweight, you will be given a different weight goal, usually 20 lbs. The weight should be gained at two pounds in the first three months, and then about four pounds a month thereafter. Ask your doctor about what you are allowed to do for exercise. It isn’t a good idea to start a vigorous exercise program after you’re pregnant, but continuing your normal exercise routine is usually encouraged. Remember that exercise lowers blood glucose, and you are already susceptible to hypoglycemia. Plan snacks before and after exercise.

Your caloric needs will increase by approximately 300 calories per day, compared with before you conceived. You also require more protein - 30 additional grams - every day. That is about four ounces of meat, fish or poultry or more dairy.  Your body will utilize carbohydrates differently throughout the day - and you will be subject to low blood sugars. Remember to eat regularly and include regular snacks. Testing your blood glucose six-eight times a day might be necessary to keep good blood glucose control. 

To treat hypoglycemia, you need to keep glucose tablets or gel readily available, as well as carbohydrate foods. You could also carry a glucagon pen to be injected if you should become incapable to eat. People around you should be made aware of the signs and symptoms of hypoglycemia and how they can help you.

One concern your obstetrician will have is typically babies of women with diabetes are larger than average. This condition, called “macrosomia,” is caused when the mother has high blood sugar that then causes the pancreas in the baby to produce more insulin, which creates more fat. The baby could grow abnormally large, and may necessitate a cesarean delivery.

During labor and delivery, your blood glucose will be carefully monitored. The baby may have very low blood glucose after birth, and this will be monitored and treated. Even though these are very special circumstances, a woman with diabetes can have a normal pregnancy and baby. Good medical care is essential. Be proactive and keep your appointments for both your health and that of your baby.

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