Although studies vary, it is estimated that gestational diabetes affects around 4 to 9 percent of pregnant women, or 4 to 9 of every 100 women who become pregnant in the United States.
It is also estimated that gestational diabetes is 100 times more common than pregestational diabetes.
There are also ethnic and racial groups that are at higher risk for gestational diabetes.
It is thought that the Pima Indians of Arizona have 40 percent chance of having gestational diabetes, or a tenfold higher risk than the general population.
Other groups are also at an increased risk, including African Americans, obese women, women who are at an older maternal age at pregnancy, women with a family history of diabetes, women whose babies are large for their gestational age, and women with a prior history of gestational diabetes during other pregnancies.
Do any groups have a lower risk of developing gestational diabetes?
Yes, it has been estimated that teenage pregnant women have a lower risk, about one-fourth lower, of developing gestational diabetes than pregnant women age 35 or older. In addition, certain studies have indicated that Asian, Asian American, and Filipino women seem to have a lower risk of developing gestational diabetes, but more studies are needed to confirm the results.
About 5 to 10 percent of women in the United States will be affected by gestational diabetes.
How can having pregestational diabetes affect a woman’s unborn child?
If a mother who has insulin-dependent diabetes has uncontrolled blood glucose, excess glucose is often transferred to the fetus.
Because of this, the baby’s system secretes an increased amount of insulin, which can cause an increase in tissue and fat deposits in the baby.
According to Stanford Children’s Health, these deposits can increase the risk of birth defects, especially during the development of the fetus’s heart, brain, spinal cord, and gastrointestinal system.
In many cases, too, the infant of a mother with pregestational diabetes is often larger than expected for the gestational age.
Can a woman develop diabetes by becoming pregnant?
N o, there is no research that supports the idea that pregnancy causes a woman to develop diabetes, but there is the possibility of developing gestational diabetes.
However, some research indicates that if a woman has had gestational diabetes, she may be at a higher risk for developing type 2 diabetes later in life.
Other research seems to indicate that breastfeeding a child will lower the mother’s risk of developing type 2 diabetes.
But overall, no true connection between becoming pregnant and developing diabetes has been shown.
In what way does gestational diabetes differ from pregestational diabetes in terms of the fetus?
According to Stanford Children’s Health, pregestational diabetes (if the mother has uncontrolled blood glucose levels) has been associated with birth defects in certain organs of the fetus as they form. Gestational diabetes generally does not cause birth defects. This may be because women who develop gestational diabetes develop it later in their pregnancy. Thus, most women will have normal blood glucose levels during the first trimester when the fetus’s organs are forming.
What is the White Classification?
The White Classification of Diabetic Pregnancies classifies the risks associated with a woman who is pregnant and has diabetes.
It was presented by American physician and researcher Priscilla White (1900, 1989), who, in 1924, joined the practice of Elliot Joslin and began caring for pregnant women who had diabetes. (She was also one of the founders of the Joslin Diabetes Center in Boston; for more information about Joslin, see the chapter “Introduction to Diabetes,” and for more about the center, see the chapter “Resources, Websites, and Apps.”) White’s system was based on a pregnant woman’s age at the onset of diabetes, the duration of the disease, and whether the woman had any vascular complications.
The class system White presented in 1949 included Class A, meaning the diagnosis of the diabetes is based on a glucose-tolerance test and deviates slightly from the normal levels.
Class B means the pregnant woman has had diabetes less than ten years, with the onset at age 20 or older, and no vascular disease.
The diabetes and associated diseases increases as the classes continued down the alphabet.
For example, class F means the pregnant woman with diabetes has nephritis, or inflammation of the kidneys.
How has the White classification changed, and how does it often cause confusion?
A s research uncovered information about diabetes, the White Classification of Diabetic Pregnancies listing changed accordingly.
Other more complex revisions were made in the classification, based on differences in research and new discoveries of how diabetes affects other parts of the body.
For example, one later classification listed class A as involving a pregnant woman having diabetes that can be controlled by diet alone, at any duration or onset age.
Class B means the onset age is older than 20, with the duration less than ten years (same as with the White classification).
But such listings also become more complicated.
For instance, also in this listing, the classes are even farther down the alphabet, such as class H, in which arteriosclerotic heart disease is clinically evident, and class T, which is listed as “prior renal transplantation,” or excessive kidney disease that led to a kidney transplant.
Still other classifications list not only other symptoms in each class but add different and/or more classes.
Thus, many researchers are now calling for a more standardized classification to simplify, yet explain the complexities of, the list of types of diabetes in pregnant women.
Is there a classification based on just gestational diabetes?
As with many diseases, there are often several classifications. Gestational diabetes also has its own classification that differs from the White and subsequent listings (see above). One of the simplest states that if a pregnant woman can control her diabetes through diet, then it is called class A1; if a pregnant woman needs insulin or oral medication to control her diabetes, then it is called class A2.
Are multiple pregnancies connected to diabetes?
Multiple pregnancies, or pregnancies with more than one fetus, often pose special risks because of the extra demands on the mother’s system.
For example, the need for oxygen and other nutrients for each fetus is multiplied.
In addition, two common health conditions often affect the mother in multiple pregnancies.
One is called preeclampsia, or having high blood pressure and protein in the urine.
The other condition is gestational diabetes, or high blood sugar levels during the pregnancy (see above).
Why is breast milk so nutritious for a baby, and how is it connected to diabetes?
After a baby is born, the mother’s breast milk becomes extremely important for the baby’s nutrition.
The milk has an amazingly consistent composition, and in most mothers, it is almost a “perfect food” for the child (although it is usually low in vitamin D and fluoride).
Certain studies indicate that breastfeeding a baby decreases the risk of respiratory infections, high blood pressure, asthma, and a tendency to develop certain allergies.
In some studies, it has been found that when a baby is breastfed, he or she will have a lower incidence of diabetes in later years.
But realistically, such benefits also depend on the mother’s lifestyle habits.
In other words, the nutrition of the breast milk is directly related to the nutrition of the mother.
And if a nursing mother has poor nutrition, then it is often the amount of milk more than the quality that suffers.
Breastfeeding is thought to be much healthier for infants than bottle feeding. One benefit is that breastfed babies have a lower incidence of developing diabetes later in life.
Can breastfeeding protect a mother from type 2 diabetes?
Although several studies seem to indicate that breastfeeding can cause certain changes in a mother’s body that may help protect against type 2 diabetes, the connection has not been proven.
But there are some indications that this may be true.
For example, one recent study looked at 1,000 ethnically diverse women who had been diagnosed with gestational diabetes.
The researchers examined each woman in terms of, for example, lactation intensity and duration.
They then tested the women’s blood glucose six to nine weeks after delivery and annually for two years after.
By that time, almost 12 percent of the women developed type 2 diabetes, and after accounting for several factors (such as age or other risk factors), the researchers found that women who exclusively breastfed or mostly breastfed were about half as likely to develop type 2 diabetes as those who did not breastfeed.
In addition, the researchers found that the length of time a woman breastfed affected her chances of developing type 2 diabetes.
Women who breastfed longer than two months lowered the risk of type 2 diabetes by almost half and beyond five months lowered the risk by more than half.
But again, more research needs to be done.
Should a mother take diabetes medication while breastfeeding?
If a mother with diabetes decides to breastfeed her baby and takes either insulin or oral medication, it is important to understand certain safety factors while breastfeeding, not only for the baby’s health but for the mother’s sake, too. According to the American Diabetes Association, most diabetes medications can be taken safely as a woman breastfeeds her baby, but the ADA strongly advocates that the woman check with her doctor just to be sure.
What are some tips for mothers who have diabetes and wish to breastfeed their infant?
According to the American Diabetes Association, breastfeeding can be a challenge for mothers who have diabetes, especially because it often makes it harder to stabilize blood glucose levels.
The organization suggests that to prevent lower blood glucose levels, the mother should plan to have a snack before or during nursing, drink plenty of fluids (such as water or a caffeine-free beverage) while nursing, and have something nearby to eat in case of low blood glucose so the child’s feeding will not be interrupted.
And as always when breastfeeding, it is best to get the right amount of fluids, nutrients, and proteins.
Such a nutritional plan can be worked out between a health care professional or dietitian and the breastfeeding mother.
GENES AND VARIOUS TYPES OF DIABETES
What are chromosomes and genes?
A chromosome is the threadlike part of a cell that contains DNA, or deoxyribonucleic acid.
It also contains the genetic material of a cell.
In some cells, the chromosomes consist entirely of DNA and are not enclosed in a membrane (called a nuclear membrane).
In other cells, the chromosomes are found within the central nucleus of the cell and contain both DNA and RNA (ribonucleic acid).
Overall, the human genome contains 24 of these distinct, physically separate units. (For more about DNA and RNA, see sidebar.) Arranged linearly along the chromosomes are tens of thousands of genes (from the Greek term genos, meaning “to give birth to”).
They are complex protein molecules and are responsible, as a unit or in biochemical combinations, for the transmission of certain inherited characteristics from the parent to the offspring, such as eye color.
The chemical structures of DNA (left) and RNA. These are the molecules so important to maintaining life processes and genes.