Gestational diabetes is a temporary type of diabetes that can develop in women during pregnancy. It presents several health risks to the mother and baby. If a woman develops a certain level of high glucose (blood sugar) during her pregnancy and has never had diabetes before, she has gestational diabetes.

About 3 to 8 percent of pregnant American women develop gestational diabetes, according to the National Institutes of Health.

As with other forms of diabetes, gestational diabetes affects the way the body handles glucose. In a normal body, the pancreas produces a hormone called insulin. Insulin helps transport glucose, the body's primary energy source, to the cells. With adequate production and efficient use of insulin, the body is able to function normally. When there is a lack of insulin or it is not being used correctly by the body, the glucose is unable to reach the cells. The glucose remains in the bloodstream, causing hyperglycemia.

With gestational diabetes, the pancreas works extra hard but it still does not make enough insulin. Without adequate insulin, the body is unable to get the necessary nutrients from the glucose in the blood. Scientists have several theories as to why insulin does not work effectively in woman with gestational diabetes. Most scientists believe the condition is related to the extra hormones produced in pregnancy, which cause greater insulin resistance.

Gestational diabetes can cause numerous problems for the mother during pregnancy. Women with this condition have a greater chance of developing preeclampsia, a potentially serious condition in which high blood pressure occurs during pregnancy. It can cause fluid buildup and swelling (edema) of the arms and legs. Preeclampsia is dangerous for the mother and the fetus, and in many cases the woman must be placed on bedrest until delivery. Gestational diabetes also raises the mother's risk of later developing type 2 diabetes.

Gestational diabetes also can cause some conditions in the fetus. However, it usually affects women late in the pregnancy rather than the critical first trimester. By the time the woman develops the condition, the baby's body has been formed and is in the growing stage. If left untreated, however, gestational diabetes can cause other problems with the fetus.

The most common problem resulting from gestational diabetes is a condition called macrosomia, a larger-than-normal baby. Definitions of macrosomia vary, such as a birth weight of 8 pounds 13 ounces, 9 pounds or 9 pounds 14 ounces for a full–term pregnancy. According to the American Diabetes Association (ADA), macrosomia occurs two to three times more often in diabetic pregnancies than in the pregnancies in the general population.

Macrosomia occurs because of high blood glucose in the mother. The glucose passes from the mother to the placenta, which in turn goes to the fetus. This causes the fetus’ pancreas to make more insulin to eliminate the extra glucose. The fetus is now getting more fuel than it needs to develop, and it stores the extra glucose as fat.

Macrosomia creates problems for the baby and the mother during delivery. The baby may suffer injuries during birth because of its large size. If the baby is too big, it may not be able to be delivered vaginally. Because of the risk of fetal macrosomia, women with diabetes are three to four times more likely to have Caesarean delivery (C-section).

There is also an increased risk of premature delivery in women with gestational diabetes. This early delivery puts the baby at higher risk for respiratory problems because the lungs are among the last organs to develop.

Gestational diabetes can also cause problems for the baby after delivery. Prior to birth, the fetus produces an increased amount of insulin to handle the mother's high blood glucose levels. At birth, the higher insulin may cause the baby to have hypoglycemia (low blood glucose). The baby's blood glucose level should be checked regularly after birth. If necessary, the baby may need early feeding or intravenous glucose to raise the blood glucose level.

Babies born to mothers with gestational diabetes have an increased risk of developing jaundice after birth. Jaundice is a yellowish discoloration of the skin and eyes that occurs when bilirubin in present in the blood. Bilirubin is a substance that is released when extra blood cells cannot be processed in the liver and build up in the blood. Jaundice usually appears within the first few days of life but sometimes may not appear until a week after birth. It can be treated by exposing the baby to special lights that remove the pigment. Although jaundice is generally not a serious condition, it should be monitored by the baby's physician.

Children of mothers with gestational diabetes are at higher risk for respiratory distress syndrome, a condition that makes it difficult for the baby to breathe. It can be treated in the hospital by supplying the baby with extra oxygen for several days to weeks depending on the severity of the disease.

Having gestational diabetes places the mother and baby at higher risk for certain problems later in life. The ADA estimates that two-thirds of women with gestational diabetes will develop the condition in subsequent pregnancies and that 40 percent of women with gestational diabetes who are obese prior to the pregnancy develop type 2 diabetes within four years. Several recent studies show that a growing proportion of women with gestational diabetes are later developing type 2 diabetes, mostly because of the obesity epidemic. The chance of developing type 2 diabetes is lower in women who are not overweight.

In addition, women with gestational diabetes may be at higher risk of heart conditions, stroke or other complications.

For the baby, gestational diabetes increases the chance of developing diabetes in the future. Babies with excessive insulin become children who are at risk for obesity and adults who are at risk for type 2 diabetes. It is important that these children adopt a healthy lifestyle early in life to help prevent diabetes.

Recent research indicates there is also an increased risk of complications to the mother and baby in cases where the woman's glucose level is above normal but not high enough for a diagnosis of gestational diabetes.

Unlike other forms of diabetes (except for some cases of secondary diabetes), gestational diabetes is considered a temporary condition. Once the baby is born and the placenta hormones are removed from the bloodstream, glucose levels typically return to normal. The woman may require regular testing after the birth of the baby to be sure her glucose is in control. With a healthy diet, normal weight and controlled blood glucose, the woman can greatly reduce chances of further complications from gestational diabetes.