October 26, 2009

Gestational Diabetes

I frequently receive emails asking me about Gestational Diabetes (GD), which is the term used for diabetes that is diagnosed only after a woman, previously considered normal, displays abnormal glucose tolerance test results during pregnancy.

Because obstetricians do a very good job of diagnosing and treating GD, I have not discussed it on my web site. If you are pregnant and have GD your doctors are almost certain to give you insulin to normalize your blood sugars. The blood sugar targets given pregnant women are much lower than those given the average person with Type 2 diabetes--low enough to ensure health. Follow them and you should avoid the problems associated with GD that were suffered by those of us whose GD was not well treated in the past.

Some women have found the chat boards at Diabetic Mommy helpful for finding support.

The real problems with GD only start after you give birth to your baby and bid goodbye to your obstetrician. Why? Because the average family doctor still appears to believe that GD is nothing more than one of the many complications of pregnancy and that if your blood sugar returned to "normal" after delivery, you need do nothing else.

The problem here is that the family doctor is all too likely to define "normal" as meaning "having an A1c under 7%" or, if he's a bit better educated 6.5%. Perhaps he won't even run an A1c test but will merely send you for a fasting glucose test. If the result comes back under 125 mg/dl, he may tell you you "aren't diabetic" and that will be that.

Unfortunately, if you have experienced a diabetic pregnancy, "that" is far from that. Because no matter how "normal" your doctor may tell you you are, you would not have developed GD unless your ability to secrete insulin was so borderline, before you started your pregnancy, that the stress of adding your baby's metabolic demands to that of your own organs exhausted it.

Relieving this stress by giving birth to your baby may return you to your previous state--but even if it does, the fact that you had GD should make you realize that your blood sugar control is only marginal, and this means that any other stressor might well push you back into full fledged diabetes.

What are those stressors? There are many.

1. Environmental pollutants that increase insulin resistance or damage the beta cells. These can include exposure to pesticides and industrial chemicals. Atrazine--a commonly used herbicide has been linked to increased insulin resistance. Arsenic, which is given off by power plants, has also been linked to diabetes. So have PCBs.

2. The use of FDA approved medications known to raise blood sugar or increase insulin resistance. These include cortisone treatment--either injections or prednisone pills, most SSRI antidepressants and the atypical antipsychotic drugs.

If you wonder if a drug you are taking can stress your blood sugar control, download the official FDA "Prescribing Information" by googling the name of the drug and the words "Prescribing Information" and look in the "Side Effects" section of the Prescribing information for the word "hyperglycemia." Drugs known to cause weight gain also may cause the same kind of stress to your marginal insulin production capacity.

You can find links to the studies that discuss environmental and pharmaceutical causes of insulin resistance and diabetes HERE

3. Gaining more weight. Though weight gain is often the result, rather than the cause of insulin resistance, if your weight gain results from overconsumption of fructose and eating a high carbohydrate diet, even a low fat one, some of your new weight is likely to be intracellular liver fat, which has only recently been recognized as a significant cause of increased insulin resistance. Carbohydrates not dietary fat turn out to be what raises the triglycerides that get deposited in the liver.

4. Autoimmune attack on the beta cells of the pancreas. A small but significant proportion of those who develop GD suffer from LADA a slow developing form of autoimmune diabetes. These people may experience a slight improvement in their blood sugars after they give birth, but over time their ability to secrete insulin will decline because there is currently no way to halt this kind of autoimmune attack.

What Can You Do?

The best approach to take if you have experienced a diabetic pregnancy is this. Once every month or two, test your blood sugar at home after meals. If you can't afford the expensive prescription strips, use the cheaper strips and meter sold at Wal-Mart under the "Relion" brand.

If you see values over 140 mg/dl one hour after eating, test more frequently. Blood sugars routinely going over 140 mg/dl are capable of damaging your beta cells leading to full fledged diabetes. Even with out diabetes blood sugars in the "pre-diabetic" range have been shown to be capable of giving you the early diabetic complications.

If you see blood sugars over 140 mg/dl an hour or more after you eat, cut back on carbohydrates using the advice you will find here:

How To Get Your Blood Sugar Under Control

Cutting back on carbohydrates is usually all most people need to regain normal blood sugars, even those who have been given diagnoses of Type 2 diabetes.

When Diet Might Not Work

If you were thin when you became pregnant and still developed Gestational Diabetes--or if you developed GD very quickly after becoming pregnant no matter what your weight, your situation may be more complex. Pregnancy often gives the first sign that a person may have one of the rarer forms of diabetes often called "Type 1.5." If you think this might be the case, read these pages:

LADA - Slow Onset Type 1 Diabetes With Some Type 2 Features

MODY - It's Not Type 1 or Type 2 But Something Else

Before you attempt to diagnose yourself, please be aware that MODY is much, much rarer than LADA. But the incidence of LADA appears to be increasing swiftly as part of the whole society-wide explosion of autoimmune disease and if you have any other autoimmune disease in the family, or have relatives diagnosed with Type 1 diabetes the chance you might have a rare form of "Type 1.5" goes way up.

It is also worth noting that while most overweight people who get GD are most likely to move on to an ultimate diagnosis of "Type 2" diabetes, overweight people also can develop autoimmune diabetes. Unfortunately, doctors often assume any overweight person must have Type 2 diabetes and do not run the tests that could diagnose LADA. No matter what you weigh, if your "Type 2 diabetes" continues to deteriorate, does not respond to oral drugs or to cutting carbohydrates, it may not be Type 2 diabetes at all.

Since LADA requires a very different kind of treatment than regular Type 2, this is significant. Oral drugs will not correct LADA and over time a person with LADA who is not given insulin can end up in the emergency room in a dangerous state called "Diabetic ketoacidosis" that happens when the pancreas stops making insulin.

So if you have had a diabetic pregnancy, and afterwards your blood sugars continue to rise, even if you cut way back on carbohydrates--especially if you have a family or personal history of other autoimmune-related disorders, such as authoimmune Thyroid disease or rheumatoid arthritis--insist that your doctor test you for the antibodies associated with Type 1 diabetes to see if you actually have LADA.

If your family doctor isn't familiar with LADA--and many are not--insist on seeing an endocrinologist, ideally one associated with a large hospital that has a medical school.

Most women who were diagnosed with GD in mid pregnancy probably do have the genetic makeup that over time leads to the development of Type 2 Diabetes. If this is your situation, and you see abnormal blood sugars after eating, you will respond strongly to cutting back on your carbohydrate intake.

And because you got warning of borderline high blood sugars early, you can rejoice because you have been given a golden opportunity to prevent your diabetes from progressing because GD gave you the warning which let you catch oncoming Type 2 diabetes very early, before it has been given a chance to ravage your organs.

Aggressive control with diet and modest exercise, aided, perhaps by metformin, if your doctor will prescribe it to you, should keep your blood sugars in the normal range for decades.

You also will want to feed your children diets that are not high in carbohydrates because chances are if you don't handle them well, neither will they. Teaching them that each meal does not have to start with bread, continue on with potatoes, and end with dessert can go a long way to helping them stay metabolically normal no matter what genes they have inherited.



Helen said...

Thanks! I did have GD and recently have been gaining weight 20 months later. This is helpful. Especially the tip about the Wal-Mart test strips.

If your beta cells do get damaged, can they ever regenerate?

Jenny said...


Despite claims from the makers of Januvia and Byetta, there is NO evidence in humans with diabetes that beta cells can regenerate.

If the beta cells are being destroyed by an autoimmune attack, there is no way of keeping them from degenerating.

However, if the beta cells are being destroyed by exposure to blood sugars over 160-180 mg/dl lowering blood sugar to normal limits can preserve those that are left, which may be enough to get you through.

Some evidence suggests normal people CAN regenerate beta cells which is why 2/3rds of obese people never get diabetes, but people with diabetic genes apparently cannot.

There are still a lot of unknowns on this subject. Doctors buy the claims that the drug rejuvenate beta cells because they don't have the time to investigate them. I have seen no evidence they do anecdotally because blood sugars start to decline after 2 years on the drugs which is the opposite of what they'd do if they were causing regeneration.

Justin said...


I just want to say thank you for posting this. It could not have come at a better time. My wife is 7 months pregnant and failed her Gestational Diabetes prescreening test (149 mg/dL). She passed the oral glucose tolerance test but after looking at the numbers I am not so sure the numbers are optimum. These are the numbers from the test:
Fasting - 83 mg/dL
1 hour - 160
2 hour - 148
3 hour - 131
This is after ingesting 100 grams of oral glucose. This was also done in the morning in a fasting state. She has a history of type 1 diabetes (father and great grand father). Her grandmother also has type 2 diabetes. She had her A1C tested a year ago and I think they were in the normal range but as you have stated this is not a good indicator for risk of developing diabetes. Please let me know if I am just overreacting or this is something to be concerned about. Thanks again for the time and effort that you put into this blog and the Blood Sugar 101 website. I apologize for this being so long.


Jenny said...


This is not something to worry yourself sick about. Just make sure that once your wife delivers she keeps checking her blood sugars from time to time.

100 g is a huge load of glucose. Testing with food is a much better way of determining how well a person's blood sugar control is doing. With meals that keep carbs moderate--no more than 30 or 40 grams at once, it is possible her blood sugar might be completely normal.

If not, lower the carbs.

The people who have to get more aggressive are those, like me, who get carbs down to 12-15 per meal and are still seeing blood sugars up near 140. That points to something that needs further treatment.

Justin said...


Thank you so much for the quick reply. I assumed that they used 50g and was surprised to see that it was 100g. Definitely a pretty big glucose load to handle. Your comments definitely put me more at ease. She is going to start testing once she has delivered. Also, hopefully we can find a good physician after the delivery that will be more receptive to our needs. We live in Richmond, VA and it has been real difficult to find someone that looks at health more holistically. Keep up the good work and I look forward to your next post.


Carrie said...

How long after a GD diagnosis would it take for LADA to progress? I had three cases of GD and all developed much earlier than the third trimester despite being slim and active. The first case was 12 years ago and the most recent was 7.5 years ago. I've recently noticed my sugars climbing up and have changed to a low carb diet. That keeps me well below the 140 one hour limit. I've stayed a healthy weight and very active. It seems like LADA would have progressed further along before now. Thanks!

Jenny said...


Sorry for the late reply. Google did not notify me that a comment had been posted.

LADA usually progresses to full fledged insulin dependence within 5 years. So you aren't likely to have it. You might have one of the forms of MODY which would also show up early in pregnancy and can lead to slow deterioration over time like you are seeing.

Carrie said...

Thank you for your response! Since I wrote I had a fasting c-peptide result which came in low (0.62 ng/ml with normal as 0.8-3.14), although my fasting glucose was normal (87 mg/dl), so I had the antibody testing for LADA. Luckily those came back negative. So, now I wait and see what happens.