What is Gestational Diabetes?

What is Gestational Diabetes?  In reality, that is a very controversial question.  Research in this area does not support current practices. This article is an overview of current practices for Gestational Diabetes.  See Treatment for Gestational Diabetes to learn more about the evidence-based view of GD.

During digestion, the body breaks down carbohydrates from foods such as bread, pasta, vegetables, fruits and dairy products into various sugar molecules. One of these sugar molecules is glucose, a main source of energy. Glucose is absorbed directly into the bloodstream after eating, but it can't enter cells without the help of insulin.

The pancreas, a gland located just behind the stomach, produces insulin continuously.  When blood sugar increases after eating, insulin production also increases. The extra insulin "unlocks" cells to more sugar, which provides the body with energy and helps maintain a normal level of sugar in the blood. 

During pregnancy, the placenta produces hormones to sustain the pregnancy. These hormones make cells more resistant to insulin. As the placenta grows larger in the second and third trimesters, it secretes more of these hormones, making it even harder for insulin to do its job. 

Normally, the pancreas responds by producing enough extra insulin to overcome this resistance. When the pancreas can't keep up, too little glucose gets into the cells and too much stays in the blood. This is called gestational diabetes.

Gestational diabetes usually develops during the second trimester, sometimes as early as the 20th week, but often not until later in the pregnancy.

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Risk factors for gestational diabetes include:

• MATERNAL AGE OVER 25
• FAMILY HISTORY OF DIABETES OR PRE-DIABETES
• EXCESS WEIGHT/BMI
• HISTORY OF POLYCYSTIC OVARIAN SYNDROME (PCOS)

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"Race" is commonly listed as a risk factor.  However, it isn't.  The truth is that when norms for GD were established, the normal blood sugar levels of different races weren't taken into account.  They were established by a study of Caucasian and African-Americans and were not separated by true diabetics vs. those with normal sugars.  Due to this fact, women who are Asian, Hispanic, and American Indian are overly diagnosed with Gestational Diabetes because their normal blood sugar levels are higher than those on whom the standards were based.  

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DIAGNOSIS

Most traditional care providers recommend a blood test known as a glucose challenge test (GCT) between 24-28 weeks of pregnancy or earlier if in a higher risk group.

You'll drink a syrupy glucose solution called glucola (usually in either a 7-up or orange soda variety). One hour later, you'll have a blood test to measure your blood sugar level.  This can be a finger stick or traditional blood draw.  A level below 130-140 milligrams per deciliter (mg/dL) is usually considered normal on a GCT, although this may vary by provider.  If your level is higher than the threshold, you should take a second test to confirm the diagnosis.  

For the follow-up test, you'll be asked to fast overnight. Then you'll drink another sweet solution with a higher concentration of glucose and your level will be checked every hour for three hours. If two of the readings are higher than normal, you'll be diagnosed with gestational diabetes.

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COMPLICATIONS FOR YOU

GD increases the risk of preeclampsia, a condition characterized by high blood pressure and excess protein in the urine after the 20th week of pregnancy. Left untreated, preeclampsia can cause serious or life-threatening complications for both you and the baby.  Once you've had GD in one pregnancy, you're more likely to have it again. You're also more likely to develop Type II Diabetes as you age, since most women with GD have the risk factors (overweight, high BMI, advanced age).  

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COMPLICATIONS FOR THE BABY

Uncontrolled Gestational Diabetes increases the risk of:


•    Low Blood Sugar

•    Respiratory Distress Syndrome

Jaundice, a yellowish discoloration of the skin and the whites of the eyes may occur if a baby's liver isn't mature enough to break down a substance called bilirubin, which normally forms when the body recycles old or damaged red blood cells. Although jaundice usually isn't a cause for concern, careful monitoring is important.

Babies of mothers who have GD have a higher risk of developing obesity and Type II Diabetes later in life.

GD can cause placental calcification, or early degeneration to the placenta, which can limit the nutrients the baby receives and lead to a stillbirth if not caught.  Placental grade can be measured via BioPhysical Profile to ensure that the baby is healthy.  Risk of stillbirth is quite low.

Extra glucose can cross the placenta, which triggers your baby's pancreas to make extra insulin. This can cause your baby to be macrosomic (have a birth weight over 4000 grams). Very large babies are more likely to become wedged in the birth canal, sustain birth injuries or require a c-section birth.  However, in well-controlled GD, babies average less than 4 ounces larger.

References

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Page Last Modified by Catherine Beier, MS, CBE