Tuesday, April 28, 2009

Thoughts on Gestational Diabetes Testing

In my quest to be as educated about pregnancy as possible, one particular area I am interested in is prenatal testing.  I have researched which tests are suggested, what each one does, and the risk/benefit analysis of each- and I started studying this even before I was pregnant. Partly due to this, and partly due to our decision to carry a pregnancy to term regardless of any test results, Brett and I have been very hands-off. That is, we've refused all the standard blood screens, first trimester NT (to look for Downs), amnio/CVS, and are only having one ultrasound, mainly to check for any issues that may need early correction or may affect my plans for a natural birth. It's my personal opinion that before anyone decides to have any of these tests, one should consider the possible responses. If termination isn't an option for you, then is testing for a potentially fatal defect really desirable? These are very personal questions, certainly, and I respect everyone's individual feelings. 

Anyways, one test that I encountered recently concerns not only the baby's health, but my own: the Gestational Diabetes test. Now, I went into my last appointment determined to refuse this one, and pretty convinced that my midwife would back me on this one. I'm going to break this down with quotes from mothering.com author Sara Buckley.

What is Gestational Diabetes? 

"GDM is mostly caused by the woman’s normal pregnancy hormones (made by the baby’s placenta), which make her body somewhat resistant to the effects of insulin. Insulin is the hormone (the body’ schemical messenger) that lowers the levels of glucose in the blood by transporting it into the cells. 

Insulin resistance means that the body is responding less to insulin (the door is not open as wide), and so less glucose enters the cell and more stays in the bloodstream, giving higher levels than usual. In pregnancy this is beneficial, as it leaves more glucose in the mother’s bloodstream,which makes more glucose available to the baby, who gets all the glucose needed for growth and development from the mother’s bloodstream, via the placenta. This transfer of glucose is dependent on the mother’s levels being higher than the baby’s.

The level of insulin resistance that an individual pregnant woman has depends on her own biochemistry and genetics, as well as her diet and activity levels. Some women, and some families, seem to get more insulin resistance than others in pregnancy, and this may reflect a slightly increased susceptibility to diabetes in later life. The baby also plays a part, because he/she can signal the mother’s body to increase glucose levels by producing more pregnancy hormones, giving more insulin resistance. As above, this is more likely to happen when the baby is big.

If the mother has a diet that includes a lot of carbohydrates with a high glycemic-index (ie foods that cause a rapid rise in blood glucose) and/or low levels of activity, her blood glucose may be higher and she may be more likely to be given this diagnosis.

So you can see that it is normal and healthy to have higher levels of glucose in pregnancy. However, when levels reach a certain point, a woman is at risk of being labeled with ‘impaired glucose tolerance’ (IGT, also called ‘pre diabetes’)and at even higher levels, with GDM."

Now that we know what it is, what does the medical community think about it? Is testing recommended? 

"GDM is a very controversial diagnosis. Some experts in the area have called it ‘a diagnosis still looking for a disease’, a ‘non-entity’ and a ‘useless diagnosis’, while others think it is so important that every pregnant woman should be tested for it. Michel Odent believes that the diagnosis of GDM causes more harm than good by labeling the pregnant woman ‘high risk’ which increases her anxiety but has no benefits for her or her baby, as below.

The US Preventative Services has not recommended routine screening and a Canadian committee of experts also concluded, ‘Until evidence is available from large randomised controlled trials that show a clear benefit from screening for glucose intolerance in pregnancy, the option of not screening for GDM is considered acceptable.’ The UK-based Cochrane database, which has analyzed the best medical evidence, also concludes that there are no benefits to treating GDM, in terms of outcome for mother and baby, which makes the diagnosis also very questionable.

Some doctors are concerned that women with GDM are more likely to have a very large (‘macrosomic’) baby, and it is true that there is an association between GDM and large babies. However, these large babies can be explained by other factors,such as the mother being overweight. Medical treatment does not seem to change this significantly, and it seems more likely that the size of the baby is causing the GDM, (because a big baby needs more glucose and so makes more hormones to increase insulin resistance) rather than GDM causing a big baby.  

International studies show that the only major outcome from making this diagnosis is to increase the risk of a caesarean."

What can you do to avoid it? 

While there are several factors that can make it more likely to have GD (weight, race, other health factors), there are some things you can do.

1. Eat a balanced diet, with plenty of protein, low-GI carbs, and quality fats

2. Exercise!!

What happens if I have it?

Treatment options vary depending on the severity of diagnosis. One thing you CAN plan on, however, is that your plans for a natural birth will likely be affected. The baby will be monitored more closely, and may be given an iv immediately after birth, preventing early breast feeding. On the bright side, you CAN push for other options to help your baby. According to La Leche League: “The best way to stabilize blood sugar and prevent hypoglycemia (low blood sugar) in all infants is prompt and frequent feedings of colostrum and human milk.”

And to bring it full circle: 

I was pretty sure my midwife would recommend that I NOT have this test. She told me the opposite: for people planning home births or birthing center births, she doesn't recommend testing unless one is experiencing severe symptoms. HOWEVER, for those having a natural, unmedicated, low-intervention hospital birth, it's best to have it. As she put it, "It can keep the hospital off our backs." In other words, being able to present a negative test result will help prevent unnecessary intervention, especially in the case of a slightly larger baby. 

For more info:


Jenny said...

I agree. I think it's overzealous and unnecessary to test every single woman for GD. And I mean, really--what are the chances of YOU having it? I am not being tested for that this time, as my midwives said it was up to me but I have none of the risk factors. I did it last time and it was negative.

I was just talking to Jordan today about those early pregnancy blood tests and whether they were really necessary. I'm going to ask my midwife later if they were required for her to legally attend my homebirth. When I was pregnant with Suzi I apparently missed getting my lab orders at the first visit, and when I went in a few weeks later the doctor was shocked that I hadn't been yet. She acted like it was some kind of problem and said I had to go right away. I don't get it.

Emily said...

Hey Jenny!

In regards to the early blood tests, my midwife (who attended homebirths for 20 years) told me that legally (in Georgia, anyways) any test can be refused- IF you sign a waiver. That's what I did to avoid having them completed. People think we're weird because most people get tested- many without knowing the percent error for them! It's crazy.

And you're right- I have no symptoms, and no risk factors for GD. But if it will help me to have the kind of birth I want, well, so be it....I keep consoling myself with the fact that my next child WILL be born at home, so these things won't be a factor then!

Tamika said...

I'm just starting now to read back thru you blog and saw this post - I've never done the GTT - but, I also had homebirths with my 2nd and 3rd. If my midwife had presented it to me as yours did - I would agree...very interesting way to present it.

As for your friend Jenny who commented - in this pregnancy I was delayed in my initial bloodwork and you would have thought my GP thought I'd totally ruined my babe for life...turns out there is two babes, but still! LOL