Gestational Diabetes

Gestational diabetes is high blood sugar (diabetes) that starts or it is first diagnosed during pregnancy.

Pregnancy and Diabetes. Source: NIH

Other Names

• Gestational Diabetes
• Gestational Diabetes Mellitus (GDM)
• Diabetes of Pregnancy
• Glucose intolerance during pregnancy

Types

• Pre-gestational diabetes: Some women may or may not know that they have diabetes before pregnancy.
  • Type I diabetics (Insulin dependent diabetics) should try to plan their pregnancies so that their blood sugars are well controlled early in the pregnancy when the fetus’ vital organs are forming.

• • Type II diabetics should also try to plan their pregnancies in order to control their blood sugars well early in the pregnancy. Also, type II diabetics may be on some types of medications that are not usually used in pregnancy and they may need to be converted over to taking injections of insulin when they are trying to conceive.

• Gestational Diabetes: Most women are screened for gestational diabetes at 28 weeks of pregnancy. If a woman is positive on the glucose tolerance test, she has gestational diabetes.^[1]

Signs and Symptoms

Usually there are no symptoms, or the symptoms are mild and not life threatening to the pregnant woman. These symptoms include:

• Blurred vision.
• Frequent infections, including those of the bladder, vagina, and skin.
• Increased thirst.
• Increased urination.
• Weight loss in spite of increased appetite.

In some cases, though, gestational diabetes can affect the pregnancy and baby:

• The baby’s body is larger than normal (macrosomia). A large baby may need to be delivered by a surgical procedure called cesarean section, instead of naturally through the vagina.
• The baby’s blood sugar is too low (hypoglycemia). Starting to breastfeed right away can help get more glucose to the baby. The baby may also need to get glucose through a tube into his or her blood.
• The baby’s skin turns yellowish and the whites of the eyes may change color (jaundice). This condition is easily treated and is not serious if treated.
• The baby may have trouble breathing and need oxygen or other help (respiratory distress syndrome).
• Rarely, the baby can die in the womb late in the pregnancy if the mother’s sugar levels are not well controlled.

Causes

Normally, the stomach and intestines digest the carbohydrates (sugar) in food into a sugar called glucose. Glucose is the body’s main source of energy and after digestion, the body moves it from the intestines into the blood.

The pancreas gland makes a hormone called insulin, that causes the glucose to go from the bloodstream into the cells in the different organs of the body. The glucose is used in the organs and their cells for energy.

Diabetes, or high blood sugar, is caused either when there is not enough insulin made by the pancreas (as in Type I Diabetes) or if the body becomes resistant to insulin. During pregnancy, certain hormones produced by the placenta can limit the actions of insulin causing the pregnant woman to be resistant to the hormone. Cells cannot get the glucose out of the blood because of the insulin resistance. Therefore, glucose levels build up in the blood, causing diabetes, or high blood sugar.

Diagnosis

Gestational diabetes is usually diagnosed between the 24th - 28th weeks of pregnancy. Pregnant women should receive an oral glucose tolerance test during this time period to screen for this condition. High risk women should also have a 1 hour glucose tolerance test with their first prenatal labs.

• Screening glucose challenge test (also known as the 1 hour GTT, or 1 hour Glucose Tolerance Test)

The patient drinks a sugary beverage that contains 50 grams of glucose. The glucose level in her blood is then checked one hour later. If the results are above normal, the patient will need to do the three hour glucose tolerance test ( 3 hour GTT).

• Oral glucose tolerance test, or three hour glucose tolerance test (3 hour GTT)

The patient eats normally for 3 days prior to the test after which she fasts overnight for at least 8 hours.

On the day of the test the patient starts with a fasting blood glucose level, then she drinks a sugary drink that contains 100 grams of glucose. Her blood glucose levels are checked at 1 hour, 2 hours, and 3 hours after the sugary drink. If two or more of the glucose levels taken are abnormal, the patient is diagnosed with gestational diabetes.^[2]

Special testing for gestational diabetes

A blood glucose meter is a small, portable machine used by people with diabetes to check their blood glucose levels. After pricking the skin with a lancet, one places a drop of blood on a test strip in the machine. The meter (or monitor) soon displays the blood glucose level as a number on the meter's digital display.

Non-stress test (NST)

A non-stress test is a simple and painless test to check fetal well being. Special monitors are placed on the pregnant woman’s abdomen to measure the baby’s heart beat and to check for any uterine contractions. The health care provider looks at the pattern of the baby's heartbeat on the monitor to see that the baby is doing well.

After the baby is born

For most women, blood sugar levels go back to normal quickly after the baby is born. Six to twelve weeks after the baby is born, the patient should have another glucose tolerance test to check her blood sugar levels to make sure that she does not have diabetes. It may be possible to prevent Type 2 Diabetes through lifestyle changes (see below).

Before getting pregnant again, the patient should have a blood sugar test up to three months before becoming pregnant to make sure her blood sugar level is normal.

Women who have had gestational diabetes should continue to be tested for diabetes or pre-diabetes every 1 to 2 years. Diagnosing diabetes or pre-diabetes early can help prevent complications such as heart disease later in life.

Type 2 diabetes risk can be decreased in the baby if the child maintains a healthy weight throughout hos or her childhood. Children who were breastfed also have a lower rate of Type 2 diabetes.^[3]

Treatment

The goals of treatment are to keep blood glucose levels within normal limits during the pregnancy and to make sure that the fetus is healthy.

The patient with gestational diabetes should:

• Learn the diabetes pregnancy diet which includes learning how to count carbohydrates(sugar).
• Learn how to check finger sticks for glucose levels using a blood glucose meter. Finger stick glucose levels are checked after meals and in the morning.
• Try to do physical exercise such as walking or swimming after meals if instructed by their physician.
• Learn how to take insulin if needed.
• Have non-stress tests (NSTs).
• Have an extra ultrasound to check the size of the baby and the amount of amniotic fluid around the baby late in the pregnancy.

Prevention

Type II diabetes can be prevented or delayed by:

• Reaching and maintaining a reasonable weight. Even if a patient stays above her ideal weight, losing 5 to 7% of her body weight is enough to make a big difference in blood glucose levels. For example, if a woman weighs 90 kilos (200 pounds), losing 4 to 7 kilos (10 to 14 pounds), can greatly reduce her chance of getting diabetes.
• Being physically active (walking, swimming, dancing) for 30 minutes most days.
• Following a healthy eating plan. Women who eat more grains, fruits, and vegetables and who cut down on fat and calories reduce their chances of developing diabetes. A dietitian can help design meal plans.

Chances of Developing Gestational Diabetes

Risk Factors

Risk of Gestational Diabetes is higher in women who^[4]:

• Are over the age 35 when pregnant.
• Are overweight or obese (fat cells make the body resistant to insulin).
• Have a family history of diabetes.
• Are of African-American, Latina, Native-American, Asian American, Asian-Indian or Pacific Islander ancestry.
• Have given birth to a previous baby who weighed more than 4 kilos (9 pounds).
• Have Polycystic Ovary Syndrome(PCOS).
• Have recurrent infections.
• Had a previous unexplained miscarriage or death of a newborn.
• Had a previous child with a birth defect.

Clinical Trials

Here are some open clinical trials in gestational diabetes:Gestational Diabetes

Epidemiology

US and Gestational Diabetes.Source:CDC

The prevalence of gestational diabetes mellitus (GDM) in the world population is influenced by various factors and is reflective of the prevalence of type 2 diabetes in that population; therefore, ethnic and racial populations that have a high prevalence of type 2 diabetes are at higher risk of GDM. In the United States, the definition of GDM and screening policies concerning GDM have changed considerably in the past 20 years and still vary substantially. Despite four international conferences aimed at developing a consensus definition for GDM worldwide, the definition and screening criteria for GDM continue to vary, making it difficult to compare prevalences between countries. Also, because GDM includes undiagnosed type 2 diabetes before pregnancy, the definition, screening strategies, and awareness of type 2 diabetes in a population ultimately influences the observed prevalence of GDM in a population.

In places with high-risk populations such as the Native American Cree, Northern Californian Hispanics, and Northern Californian Asians reported prevalence rates based on NDDG diagnostic criteria following universal screening ranging from 4.9% to 12.8%. ^[5]

Public Health

The population health impact of Gestational Diabetes Mellitus (GDM) is not limited to exposed offspring, but affects maternal health as well. Diabetes during pregnancy is a common and increasing complication of pregnancy that differentially affects racial and ethnic minority populations dependent upon their underlying risk of diabetes. Hence, an important public health priority, consistent with reducing health disparities between racial and ethnic groups, is prevention of diabetes, starting with maternal health pre- and postconception. Women who have GDM, because of their high diabetes risk and young age, are ideally suited to be targeted for lifestyle or pharmacologic interventions to delay or prevent the onset of overt diabetes. Moreover, because women who have GDM are of childbearing age, preventing or delaying the onset of overt diabetes not only improves the woman's health, but also protects future offspring from the harmful effects of elevated glucose levels in pregnancy.

References

1. ↑ Buchanan TA, Xiang AH. Gestational diabetes mellitus. J Clin Invest. 2005 Mar;115(3):485-91. Abstract Full Text PDF
2. ↑ Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Report of the expert committee on the diagnosis and classification of diabetes mellitus. Diabetes Care. 2003 Jan;26 Suppl 1:S5-20 Full Text PDF
3. ↑ Ratner RE. Prevention of type 2 diabetes in women with previous gestational diabetes. Diabetes Care. 2007 Jul;30 Suppl 2:S242-5. Full Text PDF
4. ↑ Bottalico JN. Recurrent gestational diabetes: risk factors, diagnosis, management, and implications. Semin Perinatol. 2007 Jun;31(3):176-84. Abstract
5. ↑ Hunt KJ, Schuller KL. The increasing prevalence of diabetes in pregnancy. Obstet Gynecol Clin North Am. 2007 Jun;34(2):173-99, vii. Abstract Full text PDF

External Links

• CDC Pregnancy and Diabetes: Podcast

• National Institute of Child Health and Human Development: Managing Gestational Diabetes: A Patient's Guide to a Healthy Pregnancy

• National Institute of Child Health and Human Development: Am I At Risk for Gestational Diabetes?

• National Institute of Child Health and Human Development: Managing Gestational Diabetes: A Patient’s Guide to a Healthy Pregnancy

• American College of Obstetricians and Gynecologists: Diabetes and Pregnancy

• California’s Sweet Success Program for Gestational Diabetes: Recommended fetal tests for women with Gestational Diabetes

• Daily Food Pyramid for Gestational Diabetes

• Vegetarian Daily Food Pyramid for Gestational Diabetes

• Asian Indian Daily Food Pyramid for Gestational Diabetes