Valerie Gommon Midwife’s Blog

What NOT to expect when you’re expecting, #6:Even more testing (Glucose Tolerance Testing)

Posted on: March 27, 2010

This item is reproduced (with consent) from Birth Sense a common-sense guide approach to normal birth www.themidwifenextdoor.com/?p=747.  In the UK we sometimes use a large Lucozade drink or a heavy sugar syrup drink, and we probably wouldn’t do four blood tests, probably only two, however, this test is increasingly being used for all pregnant women in the UK and I agree with the points raised in this article.  It is certainly worth discussing whether you want/need the test with your midwife.

“Of all the tests pregnant women are expected to endure, glucose testing is probably the most dreaded.  Women groan, and tell me they’ve heard horror stories from their friends about how sick the drink will make you feel, or how they couldn’t hold it down.  There are two types of glucose tests.  The first involves drinking a sugary, flat soda type of drink (called a glucola), then getting your blood sugar levels drawn one hour later.  This is a screening test only, and helps practitioners decide who needs the three-hour test.  The three-hour test involves drinking a sugary drink on an empty stomach (after fasting 12 hours), and getting four blood draws: one before you drink the glucose; and subsequent draws at one, two, and three hours after drinking the glucose.  Having elevated blood sugars on any two of these four draws confirms a diagnosis of gestation diabetes.

The mystery to me is why glucose testing continues to be performed on nearly ALL pregnant women, regardless of risk factors.   The American Diabetes Association recommends categorizing women into high-risk, average-risk, or low risk groups.

High risk women are those who begin pregnancy with a high body mass index (BMI), have a personal history of GDM, or have a strong family history of diabetes.   Other risk factors include older maternal age (over 35) and African-American, Native American, or Hispanic ethnicity.  These women should be screened in early pregnancy, and again at 24-28 weeks.

Low-risk women, who do not need to be screened, are under age 25, normal weight at onset of pregnancy, do not belong to a higher-risk ethnic group, and have no personal history of GDM, poor obstetric outcome, or family history of diabetes in a first-degree relative.

Women of average risk, who are not in the high risk category, but don’t meet all the criteria for low-risk women, should be screened at 24-28 weeks.¹

However, evidence to support these recommendations is lacking, according to the Cochrane Review and the United States Preventive Health Taskforce (USPHT).  The USPHT recommends, “Until there is better evidence, clinicians should discuss screening for GDM with their patients and make case-by-case decisions. Discussions should include information about the uncertainty of benefits and harms as well as the frequency of positive screening test results.”²

When is the last time a pregnant woman receiving typical modern obstetric care was treated on a case-by-case basis?  Most women are treated with cookie-cutter, one-size-fits-all obstetric care.

A recent study found that testing fasting blood sugar by a simple finger-stick (which a woman could do herself at home) may be just as predictive of women who need a three-hour glucose screening as the one-hour test.³  Additionally, there are other tests which are alternatives to the one-hour test, and may be  more appealing to some women.4  These tests include a pancake breakfast, or eating a specified number of jelly beans.  Concerns about these tests as substitutes are that they may not  be as accurate as the one-hour glucose in predicting which women need the three-hour test, but they are used in government health agencies, including the Indian Health Services, which serves a high-risk population.

Many of my clients say to me, “I don’t eat refined foods when I’m pregnant, so why should I drink a big glass of refined sugar?”  The politically correct answer is, “So we can have an ‘approved’ diagnosis of gestational diabetes.”  But many women would prefer not to take the glucola test, especially if they are already very health-conscious and physically fit.

I have also worked with clients by loaning a glucose meter that is calibrated to simulate identical blood sugar levels as when you get your blood drawn from your arm.  They can check a fasting blood sugar when they first wake up in the morning, and then blood sugars two hours after a typical meal, on two or three different days and times.  I believe this provides a more accurate picture of how the woman’s body is handling her normal diet, although I admit it does not give us the “official” diagnosis of gestational diabetes.

Common-sense tip for today:  Talk with your provider about the USPHT recommendations.  Are you at increased risk for GDM?  Then consider testing, whether it is glucola or an alternative.  Are you at low or average risk?  You may wish to consider skipping testing, unless it seems that the baby is growing faster than usual, you are having consistent problems with sugar in the urine, or you are experiencing symptoms such as jitteriness/dizziness/nausea.

1.  American Diabetes Association.  Gestational diabetes.  Retrieved 03/25/10 from:  http://www.diabetes.org/diabetes-basics/gestational/

2.  National Guideline Clearinghouse.  Screening for gestational diabetes mellitus.  Retrieved 03/25/10 from: http://www.guideline.gov/summary/summary.aspx?doc_id=12507&nbr=6437&ss=6&xl=999

3.  Agarwal MM, Dhatt GS, OthmanY, Gupta R.  Gestational diabetes: fasting capillary glucose as a screening test in a multi-ethnic, high-risk population. Diabetic Medicine, 2009.  Retrieved 3/13/10 from: http://www.ncbi.nlm.nih.gov/pubmed/19709144?dopt=Abstract

4.  Indian Health Services. Alternatives to oral glucola testing.  Retrieved 03/15/10 from: http://74.125.95.132/searchq=cache:EWcHFJkuecMJ:www.ihs.gov/MedicalPrograms/MCH/M/documents/AltGlu4505.doc+IHS+alternative+glucose+testing&cd=1&hl=en&ct=clnk&gl=us

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1 Response to "What NOT to expect when you’re expecting, #6:Even more testing (Glucose Tolerance Testing)"

[…] This post was mentioned on Twitter by TG (Tony-Guy) Parker, Valerie Gommon . Valerie Gommon said: New Blog Post: What NOT to expect when you’re expecting, #6:Even more testing (Glucose Tolerance Testing) http://bit.ly/b9te0y […]

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