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Gestational diabetes laboratory findings

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]

For more information regarding GDM laboratory findings please click here

Overview

Generally, a test for gestational diabetes is carried out between the 24th and 28th week of pregnancy.

If a patient is at risk for gestational diabetes (see risk factors), screening should be done earlier in the pregnancy.

Laboratory Findings

Depending on the woman’s risk and her previous test results, she may have one or more of the following tests.[1]

  • Screening glucose test
  • Oral glucose tolerance test (OGTT)

Screening glucose test

There are several tests intended to identify gestational diabetes in pregnant women. [2][3]

  • The first, called the screening glucose challenge test, is a preliminary screening test performed between 24-28 weeks. If a woman tests positive during this screening test, a second test called the Glucose Tolerance Test, may be performed.
  • The second test confirms the diagnoses.

The screening glucose challenge test is now considered as the standard test performed during the second trimester of pregnancy.


Oral glucose tolerance test

Women who are considered at risk for gestational diabetes are given a screening test called a 50 gram glucose challenge between the 24th and 28th weeks of pregnancy (those with two or more risk factors may be tested earlier). The glucose challenge is performed by giving 50 grams of a glucose drink and then drawing a blood sample one hour later to measure the level of blood glucose present. Women with a blood sugar level greater than 140 mg/dl may have gestational diabetes, and require a follow-up test called a 3-hour oral glucose tolerance test (OGTT). [4][2][3]

References

  1. “Professional Practice Committee for the Standards of Medical Care in Diabetes-2016”. Diabetes Care. 39 Suppl 1: S107–8. 2016. doi:10.2337/dc16-S018. PMID 26696673.
  2. 2.0 2.1 Carpenter MW, Coustan DR (1982). “Criteria for screening tests for gestational diabetes”. Am. J. Obstet. Gynecol. 144 (7): 768–73. PMID 7148898.
  3. 3.0 3.1 “Classification and diagnosis of diabetes mellitus and other categories of glucose intolerance. National Diabetes Data Group”. Diabetes. 28 (12): 1039–57. 1979. PMID 510803.
  4. “What I need to know about Gestational Diabetes”. National Diabetes Information Clearinghouse. National Diabetes Information Clearinghouse. 2006. Retrieved 2006-11-27. Text ” Boyd E. Metzger, M.D., Susan A. Biastre, R.D., L.D.N., C.D.E., Beverly Gardner, R.D., L.D.N., C.D.E. ” ignored (help)

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