Posted April 12, 2013 in PREGNANCY

What happens when Glucose Tolerance Test results are high?


When you start care in pregnancy, you will find yourself faced with choices regarding recommended prenatal testing. Of these, the glucose tolerance test is one that mothers often question for necessity or validity, often causing anxiety.  Understanding changes that occur in your body, with the focus and importance of being as healthy as you can be is the key to a positive pregnancy.

During pregnancy the body is in a state of physiological hormonal aberration that alters normal metabolic functions there-in. With substantial weight gain, hormonal changes and biochemical derangements, the risk of metabolic issues like diabetes mellitus, hypertension and other complications are more common in pregnant mothers. It is important to diagnose, track any abnormalities, and make necessary changes as early as possible before any metabolic issues affect the health of mother and baby.

Glucose tolerance test are conducted during the later second trimester of pregnancy, usually at 28 weeks, to assess any abnormal level in blood sugar metabolism. The principle of this test is to introduce 50 mg of glucose to pregnant mothers any time after the 26th week of pregnancy to assess the normal functioning of insulin hormone by tracking the return of blood sugar levels to normal levels.

Some mothers claim they already have a healthy diet and do not wish to take the standard test for reasons such as, their body may not be used to such a sugar overload or the 50 mg of glucose will make them feel sick. When family history shows diabetes, it is not best to avoid testing and just eat a diabetic diet.  This is not the same as knowing if your body can handle high glucose in-take, or thinking the foods that you eat are healthy and not spiking your blood sugar levels, so with a family history having the testing can be valuable information.

Why blood sugar levels get abnormal during pregnancy?

Blood sugar levels increase tremendously during pregnancy under the influence of pregnancy hormones. This is because:

  • Fetus (baby) is dependent on maternal circulation for the delivery of nutrients, oxygen and energy that is required for optimal development and nourishment.  As a defense mechanism, most pregnancy hormones decrease peripheral action or effect of insulin and decreases tissue uptake of glucose. As a result of this action of pregnancy hormones, blood sugar levels remain high so that the glucose can be utilized by the baby whenever possible.
  • During pregnancy, sudden maternal weight gain and undue fat accumulation can also increase peripheral resistance to the action of insulin that further affects the integrity of blood sugar maintaining activities and increases the concentration of glucose in the blood.

What happens when glucose tolerance test results are high?

It is very important to control blood sugar levels in the body, this is important because:

  • Increase blood sugar levels are unable to get reabsorbed by the kidney tubules and once the load of filtered glucose exceeds the reabsorption capacity of the kidneys, excess sugar and ketones start appearing in the urine that produces characteristic symptoms of gestational diabetes. This includes frequency and urgency of urination, weight gain, weakness, dizziness and signs of dehydration (increased thirst).
  • Increase in blood sugar levels that further affect the peripheral action of glucose leads to even more spillage of glucose in the urine.
  • Since fetus (baby) can absorb sugar directly from the maternal body, substantial rise in the blood sugar levels tremendously increase the capacity of the fetus to absorb glucose in the tissues leading to macrosomia. Macrosomia refers to a large sized baby since glucose has the ability to osmotically attract water and retain in tissues.

As a result of uncontrolled blood sugar levels (characterized by abnormal glucose tolerance testing), the risk of having a macrosomic baby may also increase the risk of developing the following complications:

Large baby size can cause over distension of the uterus, making the risk of premature childbirth fairly high.

  • Since normal blood sugar levels are required for the maturation of lung cells that produce surfactant, abnormally high blood sugar levels may impair the ability of fetal lungs to produce surfactant. As a result of this, the risk of respiratory distress syndrome and other infections increases tremendously.
  • Babies that are born to gestational diabetic mothers who had abnormal glucose tolerance tests throughout pregnancy are also at risk of developing hypoglycemia soon after birth, this is because, insulin is required for maintaining normal blood sugar levels in the fetal body. Fetal pancreas produces insulin in sufficient amounts to prevent hyperglycemia in the baby. When the baby is born and the source of glucose is removed, fetal pancreas requires some time to adjust to the changing hormonal and metabolic conditions and so until that time, baby develops recurrent attacks of hypoglycemia (low blood sugar).
  • Other complications like hypothermia and electrolyte abnormalities may appear soon after birth.
  • Gestational diabetes mothers are at risk of developing full blown diabetes as adults later in life.

What to do if you have an abnormal Glucose Tolerance Testing?

Your healthcare professional may carry out a few more tests to confirm if you have full-blown gestational diabetes or borderline diabetes. In either case, you may need to take extra caution with your diet and lifestyle.

  • Speak to a dietitian to make a nutritional plan that you can follow throughout your pregnancy.
  • Exercise helps to increase insulin production; taking a walk each day is beneficial.
  • You may need to speak to your primary care provider about labor stimulation before the 40th week. This is because mothers who have gestational diabetes during pregnancy are at a much higher risk of developing Polyhydramnios and other complications. Moreover, if pregnancy is allowed to progress after term ( 40 weeks) complications of shoulder dystocia, cesarean section due to macrosomia (large size of the baby) and cephalo pelvic disproportion increases tremendously.

Monitoring of blood sugar levels throughout pregnancy is very important

  • This can be achieved by performing regular blood sugar testing with the use of a glucometer or another similar device.
  • Maintain a chart where you can document your diet with foods eaten at each meal, with blood sugar readings throughout pregnancy. This way if something in your diet spikes the blood sugar level you can eliminate it from your diet.
  • Avoid direct sources of glucose for energy like fruit juices, candies or cookies.
  • If your blood sugar tests tend to stay abnormal despite diet modification, you may need medications or hypoglycemic agents to control blood sugar levels. Medications are generally not recommended to pregnant mothers due to risk of permanent damage to developing fetus; insulin is thus a preferred approach to monitor blood sugar levels.

Natural things you can do to help

The following are natural therapies and may not be supported by your doctor however, they are not harmful either:

  • Making a tea of string bean skins drinking 1-3 cups per day, also eating Jerusalem artichokes are an excellent source of inulin, a precursor to insulin production.
  • Add cucumbers to your diet as they are nourishing to the pancreas.
  • Consume fresh liver or take it in capsule form to help reduce the need for insulin.
  • Take vitamin B 6 and the mineral chromium to help with blood sugar regulation.

Charlotte Sanchez(CPM) is a Certified Professional Midwife and
Childbirth Educator of over 20 years.