More evidence needed on diagnosing gestational diabetes.

A pregnant woman

It is normal for a women to develop some insulin resistance during pregnancy.  In around 7% of women, this resistance is excessive, causing hyperglycemia, or high blood sugar.  This is known as gestational diabetes and it can have serious consequences for both mother and baby.

The test for gestational diabetes is very inconvenient, usually involving fasting and an overnight stay in hospital.  A new Cochrane systematic review looks at whether there are any simpler tests that could lead to quick and accurate diagnoses.

Unfortunately, they only found five poor quality studies that compared different ways of taking the conventional oral glucose tolerance test.  They did not find any studies that looked at the optimum stage in pregnancy to administer the test.

Appraisal hints

Readers of this review are advised to consider the following:

  • Were the tests compared against a definitive statement of disease status?
  • Were the comparisons made blind to the results of any other tests?
  • Were the reviewers too fussy?  They state that they only looked for randomised trials.  Although this is the most reliable study design for treatments, there are other ways of conducting valid research into diagnostic tests, such as a validating cohort study.  It seems likely that there might be other research using this type of study design that did not meet their inclusion criteria and therefore was not included in the review.


The full text is available from the Cochrane Library:

Farrar D, Duley L, Lawlor DA.  Different strategies for diagnosing gestational diabetes to improve maternal and infant health. Cochrane Database Syst Rev. 2011;10:CD007122

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I am an information scientist with an interest in making knowledge from systematic research more accessible to people who need it. This means you. I've been attempting this in the area of Evidence-Based Health Care since 1995. So far the results have been mixed. For some reason we expected busy clinicians to search databases and appraise papers instead of seeing patients. We also expected publishers to make the research freely available to the people who paid for it.. Ha! Hence The National Elf service.

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