Gestational diabetes is a condition that occurs during pregnancy. Like otherforms of diabetes, it involves a defect in the way the body processesand uses dietary sugars (glucose).
In gestational diabetes, the problem is in the placenta, an organ inside thewomb that attaches the embryo to the womb's wall. During a normal pregnancy,the placenta provides the baby with nourishment. In addition, it produces hormones that interfere with the body's response to insulin, a hormone involvedin regulating glucose levels in the blood. In most pregnant women, the pancreas (the gland that produces insulin), simply makes extra insulin during pregnancy to counteract the effect of these hormones. However, when a woman's pancreas cannot produce enough extra insulin, blood glucose levels stay abnormally high, and she is considered to have gestational diabetes
Most women with gestational diabetes have no recognizable symptoms. However,leaving this form of diabetes undiagnosed and untreated is risky to the developing fetus. Left untreated, a diabetic mother's blood sugar levels will be consistently high. This sugar will cross the placenta and pour into the baby'ssystem through the umbilical cord. The unborn baby's pancreas will respond to this high level of sugar by constantly putting out large amounts of insulin, allowing the fetus's cells to take in glucose, where it will be converted to fat and stored. A baby who has been exposed to constantly high levels of sugar throughout pregnancy will be abnormally large, often so large that he orshe cannot be born through the vagina, but will instead need to be born through a surgical procedure, a (cesarean section.
Furthermore, after the baby is born, it will still have an abnormally large amount of insulin. When the mother and baby are no longer attached to each other via the placenta and umbilical cord, the baby will no longer receive the mother's high level of sugar. The baby's high level of insulin, however, willvery quickly use up the glucose circulating in the baby's bloodstream. The baby is then at risk for having a dangerously low level of blood glucose (a condition called hypoglycemia). This is easily resolved by giving the baby glucose. It is important to monitor the baby's blood glucose levels.
About 1-3% of all pregnant women develop gestational diabetes. Women at riskfor gestational diabetes include those who:
- Are overweight
- Have a family history of diabetes
- Have previously given birth to a very large, heavy baby
- Have previously had a baby who was stillborn, orborn with a birth defect
- Have an excess amount of amniotic fluid (the cushioning fluid within the womb that surrounds the developing fetus)
- Are over 25 years of age
- Belong to an ethnic group known to experience higher rates of gestational diabetes (in the United States, these include Mexican-Americans, American Indians, African-Americans, as well as individuals from Asia, India, or the Pacific Islands)
- Have a previous history of gestational diabetes during a pregnancy.
Screening for gestational diabetes is a routine part of pregnancy care, usually done between the 24th and 28th week of pregnancy. Screening involves drinking a glucose solution, followed by a blood test that determines the glucoselevel.
When the screening level exceeds a certain amount, a further three-hour glucose tolerance test is performed. This involves following a special diet for three days prior to the test. Then, for 10-14 hours just before the test, the patient is instructed to eat and drink nothing except water. A blood sample isthen taken to determine the fasting glucose level, after which the patient drinks a glucose solution and has her blood tested every hour for the next three hours. If two or more of these levels are elevated over normal, then the patient is considered to have gestational diabetes.
Treatment will depend on the severity of the diabetes. Mild forms can be treated with diet (decreasing the intake of sugars and fats, in particular). Manywomen are put on strict, detailed diets, and are asked to stay within a certain range of calorie intake. Exercise is sometimes used to lower blood sugarlevels. Patients are often asked to regularly measure their blood sugar. Thisis done by poking a finger with a needle called a lancet, putting a drop ofblood on a special type of paper, and feeding the paper into a meter which determines the blood sugar level. When diet and exercise do not keep blood glucose levels within an acceptable range, a patient may need regular shots of insulin.
The prospects for women with gestational diabetes, and their babies, is generally good. Almost all such women stop being diabetic after delivering. However, some research suggests that nearly 50% of these women will develop a permanent form of diabetes within 15 years. The child of a mother with gestationaldiabetes has a greater-than-normal chance of developing diabetes sometime inadulthood. A woman who has had gestational diabetes during one pregnancy hasabout a 66% chance of having it again during any subsequent pregnancies. Women who had gestational diabetes usually are tested for diabetes at the post-partum checkup or after stopping breastfeeding.