Think Before You Drink: A Closer Look At Glucola

Heather Dessinger

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what is the gestational diabetes test

“Now, remember to eat lots of protein, missy” . . . and don’t forget those vegetables. Healthy fats are essential, of course, and don’t skip meals! You dutifully nod your head, and then look down at the bottle of glucola that’s just been handed to you.

All of a sudden you’re in a “choose your own adventure” story. Which path will you take? What are the risks and benefits of this test?

Today I’m going to share my personal process in deciding whether or to take the oral glucose challenge test (OGCT). Please keep in mind that as I wrote in my posts on the vitamin K shot and Group B Strep, “Best Boo-Boo Kisser South Of Puckett’s Gas Station” is about as official as things get for me professionally. I am not a doctor, this is not medical advice, and your decision is completely up to you. If you need some convincing on this, read my full disclaimer where I say it over and over again.

Okay, let’s jump in!

What is gestational diabetes? ^

Most doctors say we don’t really know why gestational diabetes happens, but there is a theory out there that makes a lot of sense to me personally, and it’s this:

Before modern conveniences like grocery stores, people ate what grew in their backyard. Our ancestors’ staples were sometimes starch heavy (like the maca root consumed by Peruvians), and other times they were more fat and protein-based (like the Inuit).

Our bodies do an amazing job adapting to whatever’s available, but there are certain things we all need to thrive. Glucose is a particularly essential nutrient for babies, but in some regions it can be scarce. According to this theory, our bodies adapted to the risk of scarcity by giving our babies preferential access to it during pregnancy.

How does that work? As Chris Kresser has observed, “Pregnant women are naturally insulin resistant.” In other words, increased insulin resistance is a “totally normal physiological mechanism” that increases throughout pregnancy. (source 1, source 2)

You see, normally when we eat carbs, they convert to glucose, which circulates in our blood. In response, our body releases insulin which pulls the glucose out of the blood and puts it into our cells, where it is used for energy. However, when we’re pregnant that insulin response is dampened, which essentially keeps more glucose in the blood so that it can be transferred to the baby through the placenta.

Unfortunately, sometimes blood sugar levels go too high, and that’s not good for mom or baby. It may be because we have access to more carbs/sugar than we used to historically, but other factors may play a role as well: stress, autoimmune issues and sleep deprivation for example. (source) When our blood sugar reaches unhealthy levels we have hyperglycemia, or gestational diabetes.

What are the complications of gestational diabetes? ^

Glucose is a nutrient that helps babies grow, so as you might imagine too much of it causes them to grow larger than normal for their gestational age. According to this study of over 25,000 women, the complications associated with gestational diabetes are:

  • Babies that are larger than normal for their gestational age. It’s important to note here that according to Dr. Brian M. Casey “70-80% of overgrown infants are born to women WITHOUT GDM [gestational diabetes].” (Source: Evidence Based Birth) So gestational diabetes is not the main cause of “big babies,” but it can be a cause.
  • Increased C-section rates
  • Shoulder dystocia or birth injury. Because baby is bigger than normal, their shoulders may get stuck in the birth canal during delivery.
  • Neonatal hypoglycemia (Low blood sugar)
  • Fetal hyperinsulinemia (A “condition in which there are excess levels of insulin circulating in the blood than expected relative to the level of glucose.” (source) In other words, the baby is used to receiving large amounts of glucose and has adjusted his/her insulin production accordingly. When the amount of glucose available drops after birth, the baby ends up with too much insulin.)
  • The need for neonatal intensive care
  • Newborn jaundice
  • Preeclampsia

Does GD increase the risk of infant death? No. According to the researchers, there is no association between gestational diabetes and infant deaths.

However, mothers who develop gestational diabetes do have an increased risk of developing type 2 diabetes later in life. (source)

Am I at risk? ^

As Dr. Romm writes, “According to the American Dietetic Association, pregnant women with any of the following characteristics appear to be at increased risk of developing gestational diabetes; the risk increases when multiple risk factors are present:

  • Personal history of impaired glucose tolerance or gestational diabetes in a previous pregnancy
  • Member of one of the following ethnic groups, which have a high prevalence of type 2 diabetes: Hispanic American, African American, Native American, South or East Asian, Pacific Islander
  • Family history of diabetes, especially in first-degree relatives
  • Pre-pregnancy weight ≥110% of ideal body weight or BMI >30 kg/m2, significant weight gain in early adulthood and between pregnancies, or excessive gestational weight gain
  • Maternal age >25 years of age
  • Previous delivery of a baby >9 pounds (4.1 kg)
  • Previous unexplained perinatal loss or birth of a malformed infant
  • Maternal birth weight >9 pounds (4.1 kg) or <6 pounds (2.7 kg)
  • Glycosuria at the first prenatal visit
  • Medical condition/setting associated with development of diabetes, such as metabolic syndrome, polycystic ovary syndrome (PCOS), current use of glucocorticoids, hypertension”

Women who have the following characteristics are at low risk for gestational diabetes:

  • Less than 25 years old
  • Weight normal before pregnancy
  • Member of an ethnic group with a low prevalence of GDM (According to the Mayo Clinic, “women who are black, Hispanic, American Indian or Asian are more likely to develop gestational diabetes.”)
  • No known diabetes in first-degree relatives
  • No history of abnormal glucose tolerance
  • No history of poor obstetric outcome (Source: American Diabetes Association)

What are the signs and symptoms of gestational diabetes? ^

  • Sugar in urine (revealed in a test done in your doctor or midwife’s office)
  • Unusual thirst
  • Frequent urination
  • Fatigue
  • Nausea
  • Frequent infections of bladder, vagina and skin
  • Blurred vision

Obviously, some of these symptoms are common to pregnancy even without the presence of gestational diabetes, so they cannot be used exclusively to diagnose GD.

So how do we test for gestational diabetes? ^

Normally, a woman is given “glucola”- a drink that sometimes contains an ingredient banned in other countries. The point of the test is to see how well a woman’s body handles and influx of 50 grams of glucose over the course of an hour, but obviously many women object to drinking it. If you’re considering glucola, here are some ingredients commonly found in the drink that you may want to research before deciding. . .

Common Ingredients In Glucola ^

Brominated vegetable oil

This product, which is also approved as a flame retardant, is banned in the European and Japan.

According to Aviva Romm, a midwife and MD who specializes in the health and wellness of pregnant mamas, “Research has found that brominated flame retardants build up in the body and breast milk. BVO leaves residues that accumulate in body fat, the brain, the liver, and other organs. Studies in animals demonstrate that BVO is transferred from mother’s milk to the nursing infant. BVO has been associated with heart lesions, fatty changes in the liver, and impaired growth and behavioral development, and both animal and human studies have linked BVO to neurological problems, fertility problems, changes in thyroid hormones and precocious puberty.”

In addition, the vegetable oil of choice is often soybean, which is one of the top eight most common allergens.

Modified food starch

Like autolyzed yeast extract and hydrolyzed protein, this is a cousin of MSG.

Food Dyes such as FD & C yellow #6, Red #40

Chemical food dyes pose a “rainbow of risks” – cancer, hyperactivity, and more. Children seem to be especially vulnerable to them, and yet manufacturers still use them in products consumed by children (or in this case, babies). Well, not everywhere, of course. Manufacturers use natural food dyes in other countries because the risks of synthetic dyes are acknowledged there.


This is corn sugar, which is most likely derived from GMO corn. Though it hasn’t yet made the top eight allergens, the number of individuals allergic to corn is rising.

“Natural” flavoring

Though derived from natural sources, these flavorings are made in a lab. I guess we have different definitions of what natural means.

Other possible ingredients to look into: sodium hexametaphosphate, butylated hydroxyanisole (BHA), and sodium benzoate. (There are likely more, but this is the list I compiled after calling a diagnostic lab for help locating the ingredients in just one formula.)

Glucola may cause side effects like nausea, vomiting, bloating, diarrhea, dizziness, headache and fatigue. (source) Just what everyone needs during pregnancy! Of course, we’re all going to weigh the pros and cons of this drink differently, but I think one of the most important questions to ask is . . .

How accurate is the gestational diabetes test, anyway? ^

A common misconception is that the oral glucose challenge test (OGCT) given to most women offers a definitive answer on whether or not gestational diabetes is present. In reality, it is a SCREENING test, not a DIAGNOSTIC test.

It has a 76% sensitivity rate, which means that for every 100 women that have gestational diabetes, the glucose screening test will only identify seventy-six. That means twenty-four pregnant moms will think everything is within range, when in fact they have elevated blood sugar levels. (source 1, source 2)

On the flipside, 24% of women who test positive for gestational diabetes don’t actually have it, so unless they insist on confirming with the oral glucose tolerance test (OGTT) they will be labeled as high risk for no reason and may be subject to unnecessary interventions and medical procedures.

Another problem with the OGCT/OGTT, is that “you could ‘fail’ a test in week 28 that you would have ‘passed’ had you taken it in week 24.” (17) This is because blood glucose values rise as pregnancy advances, but no adjustments are made for this.

And not only does what week you take the test matter, what time of day can affect the result as well. This study found that our response to oral glucose is tied to our circadian rhythm, and unless our rhythm is impaired we will do better on the test at 8am rather than 4pm. As you can see, there are a lot of things that can sway the results.

Now let’s say a mama gets her test done as soon as it as offered, and she schedules the test for 8am. The test comes back positive and is confirmed with an OGTT. Is it really confirmed? That’s an interesting question, which we’ll explore in the next section.

I’m paleo and I failed the test. Why? ^

I’ve recently heard about several paleo moms failing the OGCT test, which I thought was odd. After all, hasn’t the paleo diet been shown to be very effective in managing (and even sometimes reversing) diabetes?

Though it’s impossible to know the details of every case or speak definitively without double blind studies, here’s why I think the OGCT test may not be a “one-size-fits-all” diagnostic tool:

As we talked about earlier, different societies have subsisted on different staples, some which were carb heavy (which would produce large amounts of glucose in the body) and some which were low carb (which would yield smaller amounts of glucose).

What if our bodies adapt our glucose tolerance to match our diet? We know that hyperinsulinemia (too much insulin) can occur when the body expects large amounts of glucose, prepares for large amounts of glucose, and then receives less glucose than expected. The body is anticipating future needs based on past food intake.

What if the opposite is also possible? For individuals who consume fewer sugar/carbs than the standard modern diet, wouldn’t the body adjust by producing less insulin based on expected glucose load? When those individuals are given 50 grams of glucose, should we expect their bodies to handle just like a person who eats a typical modern diet?

Or to pose this question in a more interesting way . . .

What would happen if we gave African bushmen (and women) a bottle of glucola? ^

Thanks to neurobiologist and obesity researcher Dr. Stephan Guyenet, we know the answer to that question. In this post, he compares how well the Tukisenta of Papua New Guinea, African Bantu, Native Americans of central Brazil, and iKung African Bushmen handled the OGTT – the diagnostic glucose tolerance test.

The first three groups were given 100 grams of glucose (which is twice the amount given to pregnant women during the OGCT) and passed the test with flying colors. All three groups ate a diet that was very high in carbohydrates.

The last group – the iKung – typically eat a low-carb diet. When given just half the amount of glucose that the other groups received, they failed the test. Though the researchers said that they consumed adequate amounts of carbs prior to the test, Dr. Guyenet says:
“Acknowledging that prior carbohydrate intake may have played a role in the OGTT results of the San, [the researchers] made the following remark:

a retrospective dietary history (M. J. Konner, personal communication, 1971) indicated that the [San], in fact, consumed fairly large amounts of carbohydrate-rich vegetable food during the week before testing.

However, the dietary history was not provided, nor has it been published, so we have no way to assess the statement’s accuracy or what was meant by ‘fairly large amounts of carbohydrate-rich vegetable food.’ Given the fact that the San diet typically ranges from moderately low to very low in carbohydrate, I suspect they were not getting much carbohydrate as a percentage of calories.

Looking at the nutritional value of the starchy root foods they typically eat in appendix D of The !Kung San: Men, Women and Work in a Foraging Society, they are fibrous and most contain a low concentration of starch compared to a potato for example. The investigators may have been misled by the volume of these foods eaten, not realizing that they are not as rich in carbohydrate as the starchy root crops they are more familiar with.

You can draw your own conclusions, but I think the high OGTT result of the San probably reflect a low habitual carbohydrate intake, and not pre-diabetes.” (source)

So what are we supposed to think about this? Personally, it makes sense to me that the first three tribes passed the OGTT test – they were healthy individuals whose bodies were used to handling significant quantities of glucose. From what we know, the iKung were also very healthy individuals, but their bodies were not used to large amounts of glucose. Does failing the test mean they were diabetic? I don’t think so. I think their bodies had just adapted their glucose tolerance to match their diet.

Some moms who failed the OGCT requested a different type of test to confirm or rule out gestational diabetes. In the cases I’ve read, it turned out they did not have gestational diabetes. More on the alternative test later on in this post.

Who should be tested? Can I refuse this test? ^

According to Dr. Romm, “Tests should be done on the basis of individual risk. It’s rare that a test needs to be universally done – meaning that everyone gets it, pretty much no matter what. And healthy women should not be bullied into getting tests, as many pregnant women report happens when the 24 week mark rolls around signaling their doctor or midwife that it’s time for glucose testing.”

The American Congress of Obstetricians and Gynecologists (ACOG) affirms an individualized approach, saying that their guidelines “should not be construed as dictating an exclusive course of treatment or procedure. Variations in practice may be warranted based on the needs of the individual patient, resources, and limitations unique to the institution or type of practice.” (source 1, source 2)

They also affirm your right to refuse the test if you wish to. In their own words, “Pregnant women’s autonomous decisions should be respected. Concerns about the impact of maternal decisions on fetal well-being should be discussed in the context of medical evidence and understood within the context of each woman’s broad social network, cultural beliefs, and values.

In the absence of extraordinary circumstances, circumstances that, in fact, the Committee on Ethics cannot currently imagine, judicial authority should not be used to implement treatment regimens aimed at protecting the fetus, for such actions violate the pregnant woman’s autonomy.” (source)

What are the benefits of testing for gestational diabetes? ^

Obviously, the most important reason it that it may help identify gestational diabetes if present. The rate of diabetes – both in pregnant and non-pregnant individuals – is rising in our nation, and it’s definitely something we need to be aware of.

Something to keep in mind is that the recommended treatment for mild cases of gestational diabetes is typically to eat healthy, balanced meals (without going carb crazy), exercise, and monitor blood sugar. After evaluating their risk factors (or lack thereof), some people opt not to take the test because they have already made the two primary lifestyle changes that would be recommended.

However, because even slightly elevated blood sugars may have a detrimental effect, many of these women choose to test their blood sugar at home at different times of day to make sure it’s consistently within range.

What are the downsides of the OGCT test? ^

You could get a false negative, which could deprive you of helpful guidance in terms of nutrition and lifestyle. Or you could get a false positive, which would place you unnecessarily in a high-risk category. As patients, we need to be aware that a diagnosis of gestational diabetes can change the trajectory of our pregnancy. 

As Dr. Dekker writes, we “cannot underestimate the effect of ‘labeling’ women with GDM. The label of GDM has a profound effect on how healthcare providers treat women.”

Doctors tend to fear shoulder dystocia, which is associated with GD, so they are more likely to push for a c-section. They’re also more likely to recommend induction unnecessarily for a suspected “big baby,” which can result in a baby needing admission to the NICU. (As I mentioned earlier, 70-80% of “big babies” are born to moms without gestational diabetes.)

For this reason, I would personally would absolutely insist on confirming my diagnosis and discussing options thoroughly with my healthcare provider.

Are There Alternatives To Glucola? ^

Yes, there are. Here are some suggestions from Dr. Romm:
1. “If you are in your first or early second trimester, consider a Hemoglobin A1C test. It is a simple blood test that doesn’t require you to ingest anything prior. While there is no set level that determines gestational diabetes (there are levels for non-pregnancy-related diabetes), done early enough in pregnancy it can determine whether you already had undetected diabetes before even becoming pregnant, and a level of 5.45% may be associated with gestational diabetes, in which case you can make dietary changes and wait until 24-28 weeks gestation, when the glucose challenge and GTT are typically done, and then decide whether to test.

2. Consider an excellent diet and random glucose testing. This just requires finger stick blood testing which can even be done by you at home, and is a commonly used alternative for women who can’t tolerate the Glucola. However, one test result alone is not enough to diagnose or rule out GDM, so you’ll want to work with your doctor or midwife to come up with a reasonable schedule for testing and assessing your results.

[Note from Mommypotamus: Several paleo mama’s have reported that after receiving a preliminary diagnosis of gestational diabetes from the OGCT test, they opted for this method rather than the OGTT and it was determined that they did not have diabetes.]

3. Consider ‘The Jelly Bean Test.’ This test, which has you eat 28 jelly beans, which also provide 50 grams of sugar, has been popular amongst midwives for decades, and now there are GMO-free and naturally-colored brands to choose from. While some data suggests that the results are not entirely as reliable as using the oral glucose test drinks, an article published in a major obstetrics journal states that jelly beans are a reliable alternative that are actually preferred by women and have fewer side effects.” (source)

[Note from Mommypotamus: Here is a link to the study mentioned. Depending on the jelly bean you may need to consume more or less. The point is to equal 50 grams. These instructions call for 28 Brach’s jelly beans, which would equal 54 grams of sugar according to this site. However, it seems that with these natural jelly beans, you’d need to eat 54 jelly beans to equal 50 grams of sugar.

What About Juice? ^

Orange, apple and other juices are a combination of glucose and fructose. Though both are simple sugars, fructose does not stimulate insulin the same way that glucose does. (source) Because the goal here is to measure the body’s insulin response to glucose and we’re not exactly sure how much is contained in a glass of juice, I think one of the other methods is likely to be more reliable.

What Did You Do, Heather? ^

Using juice instead of glucola, I did the challenge test during my first pregnancy. At first we thought I failed, but then we realized I consumed far more sugar I was supposed to. Oops! Once we sorted through all that, I passed with flying colors. Of course, later on I realized that juice may not be an appropriate substitute for glucola, so I don’t really consider that test valid.

With my next two pregnancies, I discussed my risk factors with my midwives. Other than being over twenty-five I have none at all. Given my medical history and lifestyle (which included a mostly paleo diet with rice and potatoes added in), I opted out of testing. My urine samples were always negative for sugar during all three of my pregnancies. If I had been spilling sugar, of course I would have followed up with more testing.

My care providers were comfortable with my choice, and I personally didn’t feel the OGCT was accurate enough to rely on. (Especially since I don’t eat a modern super-high carb diet). I could have gone with at-home glucose monitoring, but given the fact that I had no symptoms associated with the condition, no sugar in my urine and no risk factors other than age it seemed like overkill. I gave birth to three healthy babies at home.

Would I do it the same way again? Honestly, probably not. Based on what I’ve learned, I would opt for the HbA1c (hemoglobin A1c) test described by Lily Nichols, RDN, CDE, CLT in this post on managing gestational diabetes with real food. It’s done during early pregnancy and is 98.4% accurate, which is significantly more accurate than the OGTT. If those results came back all clear, I would continue to monitor as I have in previous pregnancies, which was to measure sugar in urine. If the test suggested a concern, I would have followed up with at-home testing monitored by my healthcare provider.

Did you drink the glucola? Why or why not? ^

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Heather is a holistic health educator, herbalist, DIYer, Lyme and mold warrior. Since founding in 2009, Heather has been taking complicated health research and making it easy to understand. She shares tested natural recipes and herbal remedies with millions of naturally minded mamas around the world.