What is diabetes?
Diabetes is a condition where sufficient amounts of insulin are either
not produced or the body is unable to use the insulin that is produced.
Insulin is the hormone that allows glucose to enter the cells of the body
to provide fuel. When glucose cannot enter the cells, it builds up in the
blood and the body's cells literally starve to death.
Diabetes in pregnancy can have serious consequences for the mother and
the growing fetus. The severity of problems often depends on the degree of
the mother's diabetic disease, especially if she has vascular (blood
vessel) complications and poor blood glucose control. Diabetes that occurs
in pregnancy is described as:
- Gestational diabetes - when a mother who does not have
diabetes develops a resistance to insulin because of the hormones of
pregnancy. Women with gestational diabetes may be non-insulin dependent
or insulin dependent.
- Pre-existing diabetes - women who already have type I
insulin-dependent diabetes and become pregnant.
What is gestational diabetes?
Gestational diabetes is a condition in which the glucose level is
elevated and other diabetic symptoms appear during pregnancy in a woman
who has not previously been diagnosed with diabetes. In most cases, all
diabetic symptoms disappear following delivery.
Unlike pre-existing type I diabetes, gestational diabetes is not caused
by a lack of insulin, but by blocking effects of other hormones on the
insulin that is produced, a condition referred to as insulin resistance.
What causes gestational diabetes?
Although the cause of gestational diabetes is not known, there are
some theories as to why the condition occurs.
The placenta supplies a growing fetus with nutrients and water, as well
as produces a variety of hormones to maintain the pregnancy. Some of these
hormones (estrogen, cortisol, and human placental lactogen) can have a
blocking effect on insulin, which usually begins about 20 to 24 weeks into
the pregnancy.
As the placenta grows, more of these hormones are produced, and insulin
resistance becomes greater. Normally, the pancreas is able to make
additional insulin to overcome insulin resistance, but when the production
of insulin is not enough to overcome the effect of the placental hormones,
gestational diabetes results.
What are the risks factors associated with
gestational diabetes?
Although any woman may develop gestational diabetes during pregnancy, some
of the factors that may increase risk are:
- family history of diabetes
- obesity
- having given birth previously to a very large infant, a stillbirth,
or a child with a birth defect
- age (women who are older than 25 are at greater risk than younger
women)
Although increased glucose in the urine is often included in the list
of risk factors, it is not believed to be a reliable indicator for
gestational diabetes.
How is gestational diabetes diagnosed?
Gestational diabetes is diagnosed with a glucose screening test,
which, generally, involves drinking a glucose drink followed by
measurement of glucose levels after a one-hour interval.
If this test shows a blood sugar above a certain level, another test
will be performed after a few days of following a special diet. The second
test also involves drinking a glucose drink, and results are measured at
three-hour intervals.
If results of the second test are in the abnormal range, gestational
diabetes is diagnosed.
Treatment for gestational diabetes:
Specific treatment gestational diabetes will be determined by your
physician based on:
- your age, overall health, and medical history
- extent of the disease
- your tolerance for specific medications, procedures, or therapies
- expectations for the course of the disease
- your opinion or preference
Treatment for gestational diabetes focuses on keeping blood glucose
levels in the normal range. Treatment may include:
- special diet
- exercise
- daily blood glucose monitoring
- insulin injections
Possible complications for the baby:
Unlike type 1 diabetes, gestational diabetes generally does not cause
birth defects. Birth defects usually originate sometime during the first
trimester of pregnancy. They are more likely in women with pre-existing
diabetes, who may have changes in blood glucose during that time. Women
with gestational diabetes generally have normal blood sugar levels during
the critical first trimester.
The complications of gestational diabetes are usually manageable and
preventable. The key to prevention is careful control of blood sugar
levels just as soon as the diagnosis of gestational diabetes is made.
Infants of mothers with gestational diabetes are vulnerable to several
chemical imbalances, such as low serum calcium and low serum magnesium
levels, but, in general, the major problems of gestational diabetes
include:
Macrosomia - refers to a baby that is considerably larger than
normal. All of the nutrients the fetus receives come directly from the
mother's blood. If the maternal blood has too much glucose, the pancreas
of the fetus senses the high glucose levels and produces more insulin in
an attempt to use this glucose. The fetus converts the extra glucose to
fat. Even when the mother has gestational diabetes, the fetus is able to
produce all the insulin it needs. The combination of high blood glucose
levels from the mother and high insulin levels in the fetus results in
large deposits of fat which causes the fetus to grow excessively large.
Birth injury - may occur due to the baby's large size and
difficulty being born.
Hypoglycemia - refers to low blood sugar in the baby
immediately after delivery. This problem occurs if the mother's blood
sugar levels have been consistently high, causing the fetus to have a
high level of insulin in its circulation. After delivery, the baby
continues to have a high insulin level, but it no longer has the high
level of sugar from its mother, resulting in the newborn's blood sugar
level becoming very low. The baby's blood sugar level is checked after
birth, and if the level is too low, it may be necessary to give the baby
glucose intravenously.
Respiratory distress (difficulty breathing) - too much insulin
or too much glucose in a baby's system may delay lung maturation and
cause respiratory difficulties in babies. This is more likely if they
are born before 37 weeks of pregnancy.