Skipping the GD test?

mishka29 · September 2014

chicagojackie said:
Maybe your midwife lets you choose/doesn't test for it because if you come out positive she has to turn you over to another provider... $$$.

All OB providers should follow standard guidelines for prenatal care.

People don't test positive for tests they don't have. May as well skip the urine cultures and dipstick testing too, because why worry about the relationship between preterm labor and asymptomatic bacteriuria (uti)?

People love to skip tests that have a ton of medical evidence for no reason at all and then get all upset when their "choices" result in poor outcomes.

Enough dangerous things can happen that we cannot screen or plan for. Why skip the routine stuff?

I should have mentioned that I'm in Canada so the argument regarding $$$ doesn't hold water as it would in the US. Besides this midwife practice has a wait list so I'm sure someone would fill my space.

While I agree with your overall sentiment your comment that people don't test positive for things they don't have is a little crazy. There are false positives for all sorts of tests. Does that mean they should never be taken? Of course not. At no point was I advocating against the test, just exploring my options and interested to hear what others thought on the matter.

Anyway I don't want to beat a dead horse on this one. Thanks to everyone that contributed to the discussion this is all very helpful information for anyone who wants to hear some additional view points and info about the GD test.

deux · September 2014

Just have to mention that this is how most midwives approach testing in general - here are your options, here's the risk benefit profile, I'll leave it up to you, and here's what we do if you opt out. They've always talked me through testing decisions without pushing me one way or the other. There were a few things with my last pregnancy (like GBS testing) where she didn't personally have an opinion on whether or not I did it, but recommended I do it just to have it in my chart in case we had to transfer.

I'm only 18 weeks so GD hasn't come up yet, but that was the basic conversation we had about the anatomy scan. Here's what they look for, here's what most clients do, up to you whether you want it.

My experience with my last midwife and GD testing - I didn't want the glucola, so she gave me the option of using a glucometer for a few days while eating my normal diet, or just following a blood sugar control diet for the rest of my pregnancy if I didn't want to test at all. I was already pretty much following a GD compliant diet, but I did the glucometer monitoring anyway.

This time I'll probably ask for an A1C, a single blood draw with no fasting or sugar bolus. I'm eating a GD compliant diet this time as well so I'm not anticipating any issues.

chicagojackie · September 2014

I was being sarcastic to make a point about the ridiculousness or ignorance of not taking routine recommended tests. You're right! It is crazy. There is an old adage among doctors, "there can be no fever if you don't check a temperature."

Fwiw the society of obstetricians and gynecologists of Canada have the same screening recommendations as the American college so everyone board certified should be on the same page. Also just because someone is popular or has a long wait list does not make them a safe or great provider.

To @deux your MW doesn't have an opinion about GBS testing and treatment? Are they board certified?

There is a wealth of medical data and knowledge in the obstetrical and neonatal journals (British, American and Canadian) regarding this topic and neonatal group b strep disease. Even the American college of midwives supports it. Early onset group b strep disease in a newborn can be deadly. CDC even has data on their website.

Getting your vagina swabbed is no big deal compared to the neonatal sepsis NICU admission a baby could have. Babies don't choose to suffer from preventable ailments.

mrsherr22 · September 2014

I'm just wondering why you wouldn't do it? The risks of GD if unmonitored is not worth it!

mishka29 · September 2014

@chicagojackie‌ sorry, missed the sarcasm there. Tone over the internet doesn't always translate.

@sweets0022. I didn't say I wouldn't take the test but I was considering my options bc I'm considered low risk. I've added additional comments through out this post elaborating so I won't drone on about it again.

jeanzcarol · September 2014

I just want to say, do what's right for you and all this judgement about your care should be ignored. You've gotten some really good responses from people about alternatives that I'm personally looking into myself. I'm having somewhat of a back and forth with my doctor about it. I don't eat much sugar and would never, ever consume as much as is in the test. Someone referenced the test being non "evasive" but I'm assuming they meant invasive. I actually find chugging that quantity of glucose to be super invasive, and not something to be taken lightly. So I congratulate you on wanting information and doing due diligence. And I think your midwife is great.

mishka29 · September 2014

jeanzcarol said:

I just want to say, do what's right for you and all this judgement about your care should be ignored. You've gotten some really good responses from people about alternatives that I'm personally looking into myself. I'm having somewhat of a back and forth with my doctor about it. I don't eat much sugar and would never, ever consume as much as is in the test. Someone referenced the test being non "evasive" but I'm assuming they meant invasive. I actually find chugging that quantity of glucose to be super invasive, and not something to be taken lightly. So I congratulate you on wanting information and doing due diligence. And I think your midwife is great.

Thank you for your comment. I've been around the bump long enough to let any judgement slide off my back and pick out the information being shared. You are right there was some of excellent information provided about alternative testing that may interest some people. Either way its great to get more information about any tests and proceedure being done.

elephantsonpatrol · September 2014

Look, its your life and your baby. Do what you want.

As for me, an A1C test isn't even close to a replacement for a GTT. I'm not going to put my babies at risk just because I don't want to take a test.

mishka29 · September 2014

elephantsonpatrol said:

Look, its your life and your baby. Do what you want.

As for me, an A1C test isn't even close to a replacement for a GTT. I'm not going to put my babies at risk just because I don't want to take a test.

Your reply indicates that I stated I didn't want to take the test. That is not the case at all. I am considering my options and getting more information, which is why I posted about it here, to get some additional view points. Nothing wrong with a good discussion!

elephantsonpatrol · September 2014

mishka29 said:

elephantsonpatrol said:

Look, its your life and your baby. Do what you want.

As for me, an A1C test isn't even close to a replacement for a GTT. I'm not going to put my babies at risk just because I don't want to take a test.

Your reply indicates that I stated I didn't want to take the test. That is not the case at all. I am considering my options and getting more information, which is why I posted about it here, to get some additional view points. Nothing wrong with a good discussion!

I didn't say you had rejected the test. I was just saying that this isn't like the vaccine debate in that your choice won't affect my family.

Again, do what you want.

ConstanceGoodspeed · September 2014

@mishka29 I want to commend you for your patience and politeness in your responses in this post. It is really frustrating to be misunderstood but you handled it gracefully.

mrsherr22 · September 2014

I accidentally pushed report instead of like @elephantsonpatrol‌ I tried pressing back really fast so hopefully nothing happens

mamabumkin · September 2014

The statistics state that only between 5-7% of pregnant women actually suffer from GDM.

I've done a fair bit of research on this topic and as usual it is hard to pin down the efficiency of the testing method. Like so much in the medical community it is a case of "Well the test may not be that great, but it's quick, easy, and something we can get the majority of women to agree to."

This blog post links to an abstract and has some statistic numbers: The article states:

27% sensitivity

89% specificity

If a test was perfect you'd have 100% on both of these. But the test is not. In fact it is far from it.

If you want the math go to the blog post. But in general it is going to miss three times as many women who have GDM with false negatives, while giving 11% of women without GDM a false positive. That's a lot of women when EVERY pregnant woman is normally getting tested and only 5-7% prevalence of the pregnant population has GDM.

Not to mention what is in the Glucola drink. I avoid BVO in my diet. I don't see why they need artificial colors in it. I don't like the idea of shocking my system with that much sugar all at once..it's more sugar than I have in probably 4-5 days!

This medical study done in Istanbul (yes I know not the US or Canada) shows less than 5%, 3.45% and they suggest a cut off adjustment from the 140 mg/dL to 145 mg/dL since they had a higher rate of sensitivity on the test, creating less false positive test results.

Of course what the cut off numbers over here vary from state to state and even doctor office to doctor office.

Now for a kicker of an article Evidence Bath Birth has a beautifully written article about the subject here---I suggest giving it a read. She suggests that the evidence for using the current standard 50g or the 75-100g tests has improved since 2001, however there are still a lot of things they have no clue about: Excerpt --

Is the glucola test really the best way to screen for gestational diabetes?

To this day, researchers still don’t know the answers to a lot of questions about screening for gestational diabetes. This is what I gathered from reading the most up-to-date literature:

We don’t know the best screening test for gestational diabetes.
We don’t know the best time during pregnancy to screen for gestational diabetes.
We don’t know if you need to fast beforehand.
We don’t know if the best cut-off point for the test.
We don’t know if screening the entire population results in improved outcomes. (Researchers theorize that screening can improve outcomes such as large birth weight, but nobody has done a randomized, controlled trial to test this theory)

Now this article isn't against being tested. She kind of leaves it up to you. You have to ask yourself what would you do if you test positive?

Having done this test twice, once testing negative, and once testing positive -- but actually having none of the supposed issues that comes with it -- I'm opting for monitoring my blood sugar myself, for a few week span over the next couple months, because I could have a risk, but at the same time, I am not sure how much in my life I can change at this point, aside from adding more exercise to my daily activities. My diet is already good, even better than my father's diet and he has diabetes.

Maybe I'm a minority in my way of thinking about the medical tests done, but they are all done as "preventative measures." Which means the assumption is that something could be wrong and a test must be done to eliminate that assumption. Rather than assuming based on evidence that it is unlikely that something is wrong and only testing when there is evidence that suggestions something could be wrong. They blanket measure all women with tests in order to avoid malpractice law suits -- which is pretty much the reason. And the testing is sold to us as a better safe than sorry approach, much like all insurance is sold to us.

I can speak from experience the first test sucks, and I hate getting blood drawn. The second test sucks even more, because they put an IV catheter in my arm for the three hour wait and drew blood every 30 minutes (which I realize is not the norm, but it is for this hospital.) I don't want to go through it again. If my testing at home shows that I have had an increase in glucose intolerance then my doctor will be the first to know, and I will bring my journal and charting in with me so we can discuss what can be done.

I think there are safe ways to opt out of traditional testing, however I think some awareness of the possibility of a problem is always good to know, it can cause us to examine our diets, our activity level, and our lifestyle to make changes for the better. But aside from insulin injections-- the main treatment is strict dietary adjustment and scheduled exercise. That is why I think it is important to think about how you would change what you're doing right now if you were to test positive...because treatment pretty much depends on the pregnant woman's shoulders.

elephantsonpatrol · September 2014

sweets0022 said:

I accidentally pushed report instead of like @elephantsonpatrol‌ I tried pressing back really fast so hopefully nothing happens

Unfortunately the Gestapo came from me this morning! Otherwise no worries

elephantsonpatrol · September 2014

mamabumkin said:

The statistics state that only between 5-7% of pregnant women actually suffer from GDM.

I've done a fair bit of research on this topic and as usual it is hard to pin down the efficiency of the testing method. Like so much in the medical community it is a case of "Well the test may not be that great, but it's quick, easy, and something we can get the majority of women to agree to."

This blog post links to an abstract and has some statistic numbers: The article states:
27% sensitivity
89% specificity
If a test was perfect you'd have 100% on both of these. But the test is not. In fact it is far from it.
If you want the math go to the blog post. But in general it is going to miss three times as many women who have GDM with false negatives, while giving 11% of women without GDM a false positive. That's a lot of women when EVERY pregnant woman is normally getting tested and only 5-7% prevalence of the pregnant population has GDM.

Not to mention what is in the Glucola drink. I avoid BVO in my diet. I don't see why they need artificial colors in it. I don't like the idea of shocking my system with that much sugar all at once..it's more sugar than I have in probably 4-5 days!

This medical study done in Istanbul (yes I know not the US or Canada) shows less than 5%, 3.45% and they suggest a cut off adjustment from the 140 mg/dL to 145 mg/dL since they had a higher rate of sensitivity on the test, creating less false positive test results.

Of course what the cut off numbers over here vary from state to state and even doctor office to doctor office.

Now for a kicker of an article Evidence Bath Birth has a beautifully written article about the subject here---I suggest giving it a read. She suggests that the evidence for using the current standard 50g or the 75-100g tests has improved since 2001, however there are still a lot of things they have no clue about: Excerpt --

Is the glucola test really the best way to screen for gestational diabetes?
To this day, researchers still don’t know the answers to a lot of questions about screening for gestational diabetes. This is what I gathered from reading the most up-to-date literature:
We don’t know the best screening test for gestational diabetes.
We don’t know the best time during pregnancy to screen for gestational diabetes.
We don’t know if you need to fast beforehand.
We don’t know if the best cut-off point for the test.
We don’t know if screening the entire population results in improved outcomes. (Researchers theorize that screening can improve outcomes such as large birth weight, but nobody has done a randomized, controlled trial to test this theory)
Now this article isn't against being tested. She kind of leaves it up to you. You have to ask yourself what would you do if you test positive?

Having done this test twice, once testing negative, and once testing positive -- but actually having none of the supposed issues that comes with it -- I'm opting for monitoring my blood sugar myself, for a few week span over the next couple months, because I could have a risk, but at the same time, I am not sure how much in my life I can change at this point, aside from adding more exercise to my daily activities. My diet is already good, even better than my father's diet and he has diabetes.

Maybe I'm a minority in my way of thinking about the medical tests done, but they are all done as "preventative measures." Which means the assumption is that something could be wrong and a test must be done to eliminate that assumption. Rather than assuming based on evidence that it is unlikely that something is wrong and only testing when there is evidence that suggestions something could be wrong. They blanket measure all women with tests in order to avoid malpractice law suits -- which is pretty much the reason. And the testing is sold to us as a better safe than sorry approach, much like all insurance is sold to us.

I can speak from experience the first test sucks, and I hate getting blood drawn. The second test sucks even more, because they put an IV catheter in my arm for the three hour wait and drew blood every 30 minutes (which I realize is not the norm, but it is for this hospital.) I don't want to go through it again. If my testing at home shows that I have had an increase in glucose intolerance then my doctor will be the first to know, and I will bring my journal and charting in with me so we can discuss what can be done.

I think there are safe ways to opt out of traditional testing, however I think some awareness of the possibility of a problem is always good to know, it can cause us to examine our diets, our activity level, and our lifestyle to make changes for the better. But aside from insulin injections-- the main treatment is strict dietary adjustment and scheduled exercise. That is why I think it is important to think about how you would change what you're doing right now if you were to test positive...because treatment pretty much depends on the pregnant woman's shoulders.

You cite to a blog, a study and an article.

The blog and the study are about the Glucose Challenge (1 hour test), not the 3 hour GTT used to diagnose GD.

The article itself says that there is a lot of evidence to support the GTT and notes that all of the alternatives are [at best] not ready for use.

The reason its done as a screening test is that you don't want to wait for the condition to progress far enough for symptoms to show. At that point your baby might already be hurt.

chicagojackie · September 2014

@mamabumkin‌ you've got your facts wrong my dear. We do know the way to test for and study GDM. The American diabetes association and the American college of obstetricians and gynecologists sets these standards. Less than 10% of the obstetrical community meets low risk criteria and could consider not screening for diabetes if they were ok taking on those risks.

From the ADA:

"Women at low risk of gestational diabetes are younger (<25 years of age), non-Hispanic white, with normal BMI (<25 kg/m2), no history of previous glucose intolerance or adverse pregnancy outcomes associated with gestational diabetes, and no first degree relative with diabetes [7]. Only 10 percent of the general obstetric population in the United States meets ALL of these criteria for low risk of developing gestational diabetes, which is the basis for universal rather than selective screening."

chicagojackie · September 2014

@mamabumkin‌
Your understanding of statistics is also flawed.

By definition a screening test has high sensitivity meaning that it errs on the side of false positives, so that no person that actually has the disease or condition is missed. It is a more serious error to tell somebody who is sick that they are healthy.

The statistical risk is accepted because people then take a confirmatory or diagnostic or high specificity test. By definition a specific test has very few false negatives.

In the case of gestational diabetes the mother takes the screening test which is the one hour GTT. If that turns positive the practitioner starts her on an ADA diet and asks for a three hour test or a confirmatory blood test. They don't make the diagnosis based on the screening test. That wouldn't make sense.

Another example is how we test for HIV the virus that causes AIDS. Initial test is a screening test meaning that theres a high rate of false positives so we don't miss anybody. But a patient is not called with the results of this positive screening test...instead the lab runs the confirmatory or specific test for HIV, a western blot.

Don't cite sources and then interpret them incorrectly this leading to more miseducation.

chicagojackie · September 2014

@ChickenOnSunday‌ all yours baby
I'm nerdy and I know it

Come and get it

mamabumkin · September 2014

chicagojackie said:

@mamabumkin‌ Your understanding of statistics is also flawed. By definition a screening test has high sensitivity meaning that it errs on the side of false positives, so that no person that actually has the disease or condition is missed. It is a more serious error to tell somebody who is sick that they are healthy. The statistical risk is accepted because people then take a confirmatory or diagnostic or high specificity test. By definition a specific test has very few false negatives. In the case of gestational diabetes the mother takes the screening test which is the one hour GTT. If that turns positive the practitioner starts her on an ADA diet and asks for a three hour test or a confirmatory blood test. They don't make the diagnosis based on the screening test. That wouldn't make sense. Another example is how we test for HIV the virus that causes AIDS. Initial test is a screening test meaning that theres a high rate of false positives so we don't miss anybody. But a patient is not called with the results of this positive screening test...instead the lab runs the confirmatory or specific test for HIV, a western blot. Don't cite sources and then interpret them incorrectly this leading to more miseducation.

Hold your horses there chickie. First of all, getting snarky isn't necessary, especially when you are wrong. My understanding of statistics is not flawed, it is in fact your understand of them and your seeming desire to push that all women take a test that doctors recommend simply because they recommend it.

Sensitivity:

If a person has a disease, how often will the test be positive (true positive rate)?

Put another way, if the test is highly sensitive and the test result is negative you can be nearly certain that they don’t have disease.

A Sensitive test helps rule out disease (when the result is negative).Sensitivity rule out or "Snout"

Sensitivity= true positives/(true positive + false negative)

Specificity:

If a person does not have the disease how often will the test be negative (true negative rate)?

In other terms, if the test result for a highly specific test is positive you can be nearly certain that they actually have the disease.

A very specific test rules in disease with a high degree of confidence
Specificity rule in or "Spin".

Specificity=true negatives/(true negative + false positives)

You say they don't make a diagnosis based on the screening test, but just before that you said they put the woman on a diabetic diet after the screening test and before the "gold standard" of the testing the 75-100g 3 hour test. So which is it? The screening test isn't used for diagnosis and they don't immediately start a form of treatment (diet -- probably meeting with a nutritionist) or they do start the woman who screens positive on a form of treatment (diet ) until they go through the second round of tests?

I don't have the faith in the medical community like you do, apparently. When the initial testing is giving 10%+ of women false positives (which 27% sensitivity means not very sensitive and can give a lot of false positives and negatives=unreliable) for the first test, they then have to go on for the second test. I couldn't find much on the statistics for the 3 hours test as far as sensitivity and specificity goes. I'm sure it is probably there, but it was getting late last night and I wasn't in the mood for digging.

It's not miseductation-- You obviously didn't read what I wrote. I'm not against testing. Women can feel free to go do the Glucose tests if they want. Personally, I am not doing it again. I don't think the medical society has a full understanding of what happens to a woman's body when she is pregnant, hell they don't have a very good understanding of the woman's body when she isn't pregnant. Try telling your OB that you think your bowl problems are related to your hormone fluctuation...and watch them laugh at you, because no one has "proven it" in their eyes. I call bullshit to a lot of what they claim they "know" about women's health, especially when later it comes to light the thought was very, very wrong. Everything in medicine is generalized, meaning ONE SIZE FITS ALL when we are not the same. Each of us are different.

I doubled checked the math from the first link (the blog) and she is accurate in her findings for the initial glucose 1 hour test.

I linked to the medical study in Istanbul to highlight how low the numbers of the population are actually affected by the condition. It's a rather low amount of the general population of pregnant women have GDM according to their study-- though that is also a different population. The idea is to just test everyone with the hopes of finding some of those who do have it.

The third article, written by a PhD no less, was used as different side of it, but also to show that the medical community's knowledge is not complete, they still don't know a great many things. And just because one group (the ADA) says one thing, doesn't mean it's the gospel, it's just their opinion as a group based on different studies. Studies change all the time, and findings aren't always perfect.

If you look here at John Hopkins page for GDM it even states they don't have a clear understanding as to why women develop a resistance to insulin while pregnant, though the running theory is hormone related.

Now @elephantsonpatrol said " The reason its done as a screening test is that you don't want to wait for the condition to progress far enough for symptoms to show. At that point your baby might already be hurt."

While that is reasonable thinking, the description on JH's website, which I would imagine is the general description most will have, is that birth defects are not an issue with GDM, the only two main issues is Macrosomia -- a baby that is larger than normal (whatever they deem normal) and Hypoglycemia after birth. Both of these things are caused by prolonged exposure to higher blood sugar levels in the mother's blood.

Obviously there are issues that comes with having a large baby - and this can happen with or without GDM -- because some women just have large babies depending on the genetics at play. Harm comes to the baby by having high blood sugar levels from about week 24 through the end of the pregnancy.

If 3-5 or even 8% of the population of pregnant women are generally diagnosed with GDM, there is a safe assumption that at least 1-2% go undiagnosed due to testing flaws. That means however, around 90% of the population take the test and don't really need it. That other 90% (whether or not they fit the supposed criteria that the ADA and doctors in general have set forth as "low risk") don't develop the insulin resistance due to what they think is an over abundance of a hormone created in the placenta.

I do believe the OP asked for thoughts on the idea of skipping the traditional Glucose screening test. That is what I was giving her my opinion based on my research, what I've already talked to my doctor about (seeing an OB right now) and what else can be done.

Considering that we are all only around or getting close to the 20 week mark, we still have a month to think on these things. If it is a concern now would be the time to start considering diet change and adding exercise, even if you plan on being screen, because the screening isn't perfect, since it is only catching a small portion of the women who actually have GDM, leaving others who have it to not go on to a second round of testing and their GDM is then unknown about until complications with birth happens.

My doctor is on board with the way I want to test myself, since it gives a longer time period with a more accurate view of how my body is handling my daily diet, which drinking a large dose of sugar (which would shock my lower sugar intake body) and may not produce accurate results. My doctor also thought my alternative was far more proactive than simply refusing the test.

We as women are fully allowed to refuse any and all testing offered as a general course of action by doctors while we are pregnant. They may guilt you, shame you, or try to coerce you into doing a test -- just as many other people may try as well, but it is our body our choice. Just doing a test for the sake of doing it because it's recommended isn't necessarily informed or being proactive about your own health. It's simply following guidelines set forth by some committee. I like to be the one in charge of my own health, not just going by what a group or committee or even doctor says.

elephantsonpatrol · September 2014

You say they don't make a diagnosis based on the screening test, but just before that you said they put the woman on a diabetic diet after the screening test and before the "gold standard" of the testing the 75-100g 3 hour test. So which is it? The screening test isn't used for diagnosis and they don't immediately start a form of treatment (diet -- probably meeting with a nutritionist) or they do start the woman who screens positive on a form of treatment (diet ) until they go through the second round of tests?

I don't have the faith in the medical community like you do, apparently. When the initial testing is giving 10%+ of women false positives (which 27% sensitivity means not very sensitive and can give a lot of false positives and negatives=unreliable) for the first test, they then have to go on for the second test. I couldn't find much on the statistics for the 3 hours test as far as sensitivity and specificity goes. I'm sure it is probably there, but it was getting late last night and I wasn't in the mood for digging.

Now @elephantsonpatrol said " The reason its done as a screening test is that you don't want to wait for the condition to progress far enough for symptoms to show. At that point your baby might already be hurt."

While that is reasonable thinking, the description on JH's website, which I would imagine is the general description most will have, is that birth defects are not an issue with GDM, the only two main issues is Macrosomia -- a baby that is larger than normal (whatever they deem normal) and Hypoglycemia after birth. Both of these things are caused by prolonged exposure to higher blood sugar levels in the mother's blood.

You are not diagnosed after the 1 hour. Otherwise there wouldn't be a 3 hour. Normally if you fail the 1 hr, you take the 3 hour within a few days. I speak from experience, I failed the 1 hour and barely passed the 3 hour a few weeks ago. It wasn't fun, but I know what I am facing and am able to prepare.

The effects of Gestational Diabetes on your baby is no joke. It can cause preterm labor not to mention breathing problems, shoulder injuries and your baby is at higher risk for regular diabetes in the future.

Doctors don't know everything. But they know a hell of a lot more than you or I about medicine. Just like I know a hell of a lot more about my area of the law then a layperson. As you say, Mothers are allowed to refuse testing. But if anyone is still reading this thread, I hope they don't reduce this test lightly.

HeyStVincent · September 2014

I could be wrong about this, but I think the glucola (or 1 hr/3hr GTT) may also be needed to truly assess your GDM risk (GDM = gestational diabetes mellitus). As other posters have mentioned, an A1c is an excellent indicator of your blood sugar control over time. A1c is an awesome indicator of blood sugar control and diabetes risk in both pregnant and non-pregnant people (much better than a stand-alone BG test that shows what your glucose looks like at a single point in time). BUT here's why I think the GTT is also important:

If you're going to develop GDM, it's not common for it to start immediately after you get pregnant. It usually doesn't show up until you're well into your second trimester. If it shows up prior to that (especially during first trimester), you may have had diabetes prior to getting pregnant and just didn't know it yet. Anyway, point being, an A1c may not show much of anything if you've just started developing GDM (because it's looking at your blood sugar over three mos...if your BG has started to elevate for the past couple of weeks, your A1c may not be significantly elevated...yet), whereas the GTT would be more likely to show this new dysfunction in BG levels.

I honestly think it would be a good idea to use A1c in conjunction with the GTT to determine what is actually going on with your blood glucose levels. I have looked at NO research on this though...this is just my personal thought based on my understanding of what both tests will show you and my general knowledge of GDM.

Edit: missing letters from words. All of the words.

HeyStVincent · September 2014

Wait a second. HOLD THE PHONE. The following was just said, and it needs to be clarified:

While that is reasonable thinking, the description on JH's website, which I would imagine is the general description most will have, is that birth defects are not an issue with GDM, the only two main issues is Macrosomia -- a baby that is larger than normal (whatever they deem normal) and Hypoglycemia after birth. Both of these things are caused by prolonged exposure to higher blood sugar levels in the mother's blood. "

I am about to explain why the above thinking is somewhat incorrect.

First, untreated GDM may put mom at a higher risk of developing preeclampsia (we could discuss why this may be though...it may be more likely that the women who are at risk of developing GDM are also already at a higher risk of preeclampsia). Untreated GDM also puts mom at a higher risk of c-section. This need for a c-section is likely due to the macrosomia that develops secondary to uncontrolled GDM. GDM is also significantly associated with a small (but real) increased risk for preterm birth: https://www.ncbi.nlm.nih.gov/pubmed/14551018

So let's talk about macrosomia and what that means for mom and baby:

Macrosomia is a little different from large for gestational age. Macrosomic babies tend to be very large through their heads and shoulders/chest - disproportionately so compared to an LGA baby. This abnormally large head and shoulder/chest makes a shoulder distocia more likely. Shoulder distocia is an obstetric emergency - you have to get the baby out quickly or it can suffocate and die. The large head and shoulders also makes delivery more difficult, and thus, makes a c-section more likely.

Here is a picture of a macrosomic baby: https://emedicine.medscape.com/article/262679-overview. You can see how the proportioning is different compared to a "normal size" baby or even an LGA baby.

Next, let's talk about hypoglycemia in newborns and what that means:

The brain needs glucose to function. You and I would not be doing too well if our blood glucose reading was below 50. The same goes for an infant - especially an infant. Babies need to work on breathing when they're born, particularly if they are born preterm (remember GDM may put you at greater risk of preterm delivery). If baby is born early, the baby may have breathing problems related to prematurity. Hypoglycemia of the newborn causes breathing problems. Google neonatal hypoglycemia and respiratory distress - it's not good. This is from Medscape, which is a much better reference on medical conditions than any blog will ever be:

"Neonatal hypoglycemia, defined as a plasma glucose level of less than 30 mg/dL (1.65 mmol/L) in the first 24 hours of life and less than 45 mg/dL (2.5 mmol/L) thereafter, is the most common metabolic problem in newborns. Major long-term sequelae include neurologic damage resulting in mental retardation, recurrent seizure activity, developmental delay, and personality disorders. Some evidence suggests that severe hypoglycemia may impair cardiovascular function.

Signs and symptoms

Infants in the first or second day of life may be asymptomatic or may have life-threatening central nervous system (CNS) and cardiopulmonary disturbances. Symptoms can include the following:

Hypotonia
Lethargy, apathy
Poor feeding
Jitteriness, seizures
Congestive heart failure
Cyanosis
Apnea
Hypothermia"

Now, to the point of the above quoted article, babies that are at higher risk of developing the severe side effects of hypoglycemia, probably have an in-born metabolic error. That said, a baby born to a mother with GDM who struggles with hypoglycemia shortly after birth will have just one more thing against it if it's got other problems - and the baby's hypoglycemia DOES impact respiratory function and ability to thermoregulate when the mother had uncontrolled GDM. https://www.urmc.rochester.edu/Encyclopedia/Content.aspx?ContentTypeID=90&ContentID=P01961

Yes, the problems of macrosomia and hypoglycemia ARE caused by prolonged exposure to too much of extra sugar in mom's blood. You are also correct in stating that GDM is NOT significantly associated with birth defects (as GDM doesn't really develop until later in the pregnancy when birth defects are already in place). That said hypoglycemia will put your baby in the NICU and prolong your hospital stay, and it comes with a whole host of nasty complications. Macrosomia increases the risk of c-section and shoulder distocia. These are all things we should avoid if we can.

Just wanted to clarify.

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