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What is self blood
glucose monitoring?
Once you are diagnosed as having gestational diabetes, you and
your health care providers will want to know more about your day-to-day
blood sugar levels. It is important to know how your exercise habits and
eating patterns affect your blood sugars. Also, as your pregnancy
progresses, the placenta will release more of the hormones that work
against insulin. Testing your blood sugar level at important times
during the day will help determine if proper diet and weight gain have
kept blood sugar levels normal or if extra insulin is needed to help
keep the fetus protected.
Self blood glucose
monitoring is done by using a special device to obtain a drop of your
blood and test it for your blood sugar level. Your doctor or other
health care provider will explain the procedure to you. Make sure that
you are shown how to do the testing before attempting it on your own.
Some items you may use to monitor your blood sugar levels are:
Lancet–a disposable, sharp needle-like sticker for pricking the
finger to obtain a drop of blood.
Lancet device–a springloaded finger sticking device.
Test strip–a chemically treated strip to which a drop of blood
is applied.
Color chart–a chart used to compare against the color on the
test strip for blood sugar level.
Glucose meter–a device which “reads” the test strip and
gives you a digital number value.
Your health care provider can advise you where to obtain the
self-monitoring equipment in your area. You may want to inquire if any
places rent or loan glucose meters, since it is likely you won't be
needing it after your baby is born.
How often and when should I test?
You may need to test your blood several times a day. Generally,
these times are fasting (first thing in the morning before you eat) and
2 hours after each meal. Occasionally, you may be asked to test more
frequently during the day or at night. As each person is an individual,
your health care provider can advise the schedule best for you.
How should I record my test results?
Most manufacturers of glucose testing products provide a record
diary, although some health care providers may have their own version. A
Self Blood Glucose Monitoring Diary is included at the end of this book.
You should record any test
result immediately because it's easy to forget what the reading was
during the course of a busy day. You should always have this diary with
you when you visit your doctor or other health care provider or when you
contact them by phone. These results are very important in making
decisions about your health care.
Are there any other tests I should know about?
In addition to blood testing, you may be asked to check your
urine for ketones. Ketones are by-products of the breakdown of fat and
may be found in the blood and urine as a result of inadequate insulin or
from inadequate calories in your diet. Although it is not known whether
or not small amounts of ketones can harm the fetus, when large amounts
of ketones are present they are accompanied by a blood condition,
acidosis, which is known to harm the fetus. To be on the safe side, you
should watch for them in your urine and report any positive results to
your doctor.
How do I test for ketones?
To test the urine for ketones, you can use a test strip similar
to the one used for testing your blood. This test strip has a special
chemically treated pad to detect ketones in the urine. Testing is done
by passing the test strip through the stream of urine or dipping the
strip in and out of urine in a container. As your pregnancy progresses,
you might find it easier to use the container method. All test strips
are disposable and can be used only once. This applies to blood sugar
test strips also. You cannot use your blood sugar test strips for urine
testing, and you cannot use your urine ketone test strips for blood
sugar testing.
When do I test for ketones?
Overnight is the longest fasting period, so you should test your
urine first thing in the morning every day and any time your blood sugar
level goes over 240 mg/dl on the blood glucose test. It is also
important to test if you become ill and are eating less food than
normal. Your health care provider can advise what's best for you.
Is it ever necessary to take insulin?
Yes, despite careful attention to diet some women's blood sugars
do not stay within an acceptable range. A pregnant woman free of
gestational diabetes rarely has a blood glucose level that exceeds 100
mg/dl in the morning before breakfast (fasting) or 2 hours after a meal.
The optimum goal for a gestational diabetic is blood sugar levels that
are the same as those of a woman without diabetes.
There is no absolute blood
sugar level that necessitates beginning insulin injections. However,
many physicians begin insulin if the fasting sugar exceeds 105 mg/dl or
if the level 2 hours after a meal exceeds 120 mg/dl on two separate
occasions. Blood sugar levels measured by you at home will help your
doctor know when it is necessary to begin insulin. The ability to
perform self blood glucose monitoring has made it possible to begin
insulin therapy at the earliest sign of high sugar levels, thereby
preventing the fetus from being exposed to high levels of glucose from
the mother's blood.
Will my baby be healthy?
The ultimate concern of any expectant mother is, “Will my baby
be all right?” There is an array of simple, safe tests used to assess
the condition of the fetus before birth and these can be particularly
valuable during a pregnancy complicated by gestational diabetes. Tests
that may be given during your pregnancy include:
Ultrasound.
Ultrasound uses short pulses of highfrequency, lowintensity
sound waves to create images. Unlike x-rays, there is no radiation
exposure to the fetus. First used during World War II to detect enemy
submarines below the surface of the water, ultrasound has since been
used safely in obstetrics. Occasionally, the date of your last menstrual
period is not sufficient to determine a due date. Ultrasound can provide
an accurate gestational age and due date that may be very important if
it is necessary to induce labor early or perform a cesarean delivery.
Ultrasound can also be used to determine the position of the placenta if
it is necessary to perform an amniocentesis (another test discussed
later).
Fetal movement records.
Recording fetal movement is a test you can do by yourself to help
determine the condition of the baby. Fetal activity is generally a
reassuring sign of well-being. Women are often asked to count fetal
movements regularly during the last trimester of pregnancy. You may be
asked to set aside specific times to lie down on your back or side and
count the number of times the baby moves or kicks. Three or more
movements in a 2-hour period is considered normal. Contact your
obstetrician if you feel fewer than three movements to determine if
other tests are needed.
Fetal monitoring.
Modern instruments make it possible to monitor the baby's heart rate
before delivery. Currently, there are two types of fetal monitors —
internal and external. The internal monitor consists of a small wire
electrode attached directly to the scalp of the fetus after the
membranes have ruptured. The external monitor uses transducers secured
to the mother's abdomen by an elastic belt. One transducer records the
baby's heart rate by a sensitive microphone called a doppler. The other
transducer measures the firmness of the abdomen during a contraction of
the uterus. It is a crude measure of the strength and frequency of
contractions. Fetal monitoring is the basis for the non-stress test and
the oxytocin challenge test described below.
Non-stress test.
The “nonstress” test refers to the fact that no medication is
given to the mother to cause movement of the fetus or contraction of the
uterus. It is often used to confirm the well-being of the fetus based on
the principle that a healthy fetus will demonstrate an acceleration in
its heart rate following movement. Fetal activity may be spontaneous or
induced by external manipulation such as rubbing the mother's abdomen or
making a loud noise above the abdomen with a special device. When
movement of the fetus is noted, a recording of the fetal heart rate is
made. If the heart rate goes up, the test is normal. If the heart rate
does not accelerate, the fetus may merely be “sleeping”; if, after
stimulation, the fetus still does not react, it may be necessary to
perform a “stress test” (oxytocin challenge test).
Stress test (oxytocin challenge test).
Labor represents a stress to the fetus. Every time the uterus contracts,
the fetus is momentarily deprived of its usual blood supply and oxygen.
This is not a problem for most babies. However, some babies are not
healthy enough to handle the stress and demonstrate an abnormal heart
rate pattern. This test is often done if the non-stress test is
abnormal. It involves giving the hormone oxytocin (secreted by every
mother when normal labor begins) to the mother to stimulate uterine
contractions. The contractions are a challenge to the baby, similar to
the challenge of normal labor. If the baby's heart rate slows down
rather than speeds up after a contraction, the baby may be in jeopardy.
The stress test is considered more accurate than the nonstress test.
Nevertheless, it is not 100 percent foolproof and your obstetrician
may want to repeat it on another occasion to ensure its accuracy. Most
women describe this test as mildly uncomfortable but not painful.
Amniocentesis.
Amniocentesis is a method of removing a small amount of fluid from the
amniotic sac for analysis. Either the fluid itself or the cells shed by
the fetus into the fluid can be studied. In midpregnancy the cells in
amniotic fluid can be analyzed for genetic abnormalities such as Down
syndrome. Many women over the age of 35 have amniocentesis for just this
reason. Another important use for amniocentesis late in pregnancy is to
study the fluid itself to determine if the lungs of the fetus are mature
and able to withstand early delivery This information can be very
important in deciding the best time for a woman with Type I diabetes to
deliver. It is not done as frequently to women with gestational
diabetes.
Amniocentesis can be
performed in an obstetrician's office or on an outpatient basis in a
hospital. For genetic testing, amniocentesis is usually performed around
the 16th week when the placenta and fetus can be located easily with
ultrasound and a needle can be inserted safely into the amniotic sac.
The overall complication rate for amniocentesis is less than 1 percent.
The risk is even lower during the third trimester when the amniotic sac
is larger and easily identifiable.
Does gestational diabetes affect labor and delivery?
Most women with gestational diabetes can complete pregnancy and
begin labor naturally. Any pregnant woman has a slight chance (about 5
percent) of developing preclampsia (toxemia), a sudden onset of high
blood pressure associated with protein in the urine, occurring late in
pregnancy. If preclampsia develops, your obstetrician may recommend an
early delivery. When an early delivery is anticipated, an amniocentesis
is usually performed to assess the maturity of the baby's lungs.
Gestational diabetes, by
itself, is not an indication to perform a cesarean delivery, but
sometimes there are other reasons your doctor may elect to do a
cesarean. For example, the baby may be too large (macrosomic) to deliver
vaginally, or the baby may be in distress and unable to withstand
vaginal delivery. You should discuss the various possibilities for
delivery with your obstetrician so there are no surprises.
Careful control of blood
sugar levels remains important even during labor. If a mother's blood
sugar level becomes elevated during labor, the baby's blood sugar level
will also become elevated. High blood sugars in the mother produce high
insulin levels in the baby. Immediately after delivery high insulin
levels in the baby can drive its blood sugar level very low since it
will no longer have the high sugar concentration from its mother's
blood.
Women whose gestational
diabetes does not require that they take insulin during their pregnancy,
will not need to take insulin during their labor or delivery. On the
other hand, a woman who does require insulin during pregnancy may be
given insulin by injection on the morning labor begins, or in some
instances, it may be given intravenously throughout labor. For most
women with gestational diabetes there is no need for insulin after the
baby is born and blood sugar level returns to normal immediately. The
reason for this sudden return to normal lies in the fact that when the
placenta is removed the hormones it was producing (which caused the
insulin resistance) are also removed. Thus, the mother's insulin is
permitted to work normally without resistance. Your doctor may want to
check your blood sugar level the next morning, but it will most likely
be normal.
Should I expect my baby to have any problems?
One of the most frequently asked questions is, “Will my baby
have diabetes?” Almost universally the answer is no. However, the baby
is at risk for developing Type II diabetes later in life, and of having
other problems related to gestational diabetes, such as hypoglycemia
(low blood sugar) mentioned earlier. If your blood sugars were not
elevated during the 24 hours before delivery, there is a good chance
that hypoglycemia will not be a problem for your baby. Nevertheless, a
neonatologist (a doctor who specializes in the care of newborn infants)
or other doctor should check your baby's blood sugar level and give
extra glucose if necessary.
Another problem that may
develop in the infant of a mother with gestational diabetes is jaundice.
Jaundice occurs when extra red blood cells in the baby's circulation are
destroyed, releasing a substance called bilirubin. Bilirubin is a
pigment that causes a yellow discoloration of the skin (jaundice). A
minor degree of jaundice is common in many newborns. However, the
presence of large amounts of bilirubin in the baby's system can be
harmful and requires placing the baby under special lights which help
get rid of the pigment. In extreme cases, blood transfusions may be
necessary.
Will I develop diabetes in the future?
For most women gestational diabetes disappears immediately after
delivery. However, you should have your blood sugars checked after your
baby is born to make sure your levels have returned to normal. Women who
had gestational diabetes during one pregnancy are at greater risk of
developing it in a subsequent pregnancy. It is important that you have
appropriate screening tests for gestational diabetes during future
pregnancies as early as the first trimester.
Pregnancy is a kind of
“stress test” that often predicts future diabetic problems. In one
large study more than onehalf of all women who had gestational
diabetes developed overt Type II diabetes within 15 years of pregnancy.
Because of the risk of developing Type II diabetes in the future, you
should have your blood sugar level checked when you see your doctor for
your routine checkups. There is a good chance you will be able to
reduce the risk of developing diabetes later in life by maintaining an
ideal body weight and exercising regularly.
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