Oral glucose tolerance testing at gestational weeks < or =16 could predict or exclude subsequent gestational diabetes mellitus during the current pregnancy in high risk group

Eur J Obstet Gynecol Reprod Biol. 2005 Jul 1;121(1):51-5. doi: 10.1016/j.ejogrb.2004.11.006.

Abstract

Background: An oral glucose tolerance test with a result that is negative but close to the diagnostic cut-off in early pregnancy was hypothesized to serve as a predictor of subsequent gestational diabetes in a high risk group. The aim of the study was to determine those cut-off values of OGTT at gestational weeks < or =16, which can predict or exclude subsequent onset of GDM in a high risk group.

Methods: Pregnant women at high risk of gestational diabetes (n = 163) underwent a 2-h, 75-g oral glucose tolerance test at gestational weeks < or =16 were analyzed in this study. In the event of a negative result, subsequent oral glucose tolerance tests were performed at gestational weeks 24-28 and 32-34. The sensitivity, the specificity, the positive and negative predictive values and the Odds ratio of the best cut-off values of fasting and postload glucose levels were calculated.

Results: The best cut-off values to exclude subsequent GDM for fasting and postload glucose were 5.0 and 6.2 mmol/l, respectively. In combination, the best cut-off values were 5.3 mmol/l for fasting and 6.8 mmol/l for postload glucose, with negative predictive values of 0.97 and 0.71 and sensitivities of 96.9 and 86.3 at gestational weeks 24-28 and 32-34, respectively. Combination of these cut-off values with obesity proved to be very predictive for gestational diabetes by gestational weeks 32-34, with an Odds ratio of 6.0 [95% confidence interval: 1.7-21.0].

Conclusions: With regard to the very high negative predictive value of the method, pregnant women with glucose levels of < or =5.3 mmol/l at fasting and of < or = 6.8 mmol/l at postload in gestational weeks < or =16 should undergo subsequent oral glucose tolerance testing merely at gestational weeks 32-34. Approximately a quarter (24.5%) of the pregnant women at risk of gestational diabetes satisfied these criteria.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Age Distribution
  • Blood Glucose / analysis
  • Confidence Intervals
  • Diabetes, Gestational / diagnosis*
  • Diabetes, Gestational / epidemiology*
  • Female
  • Glucose Tolerance Test
  • Humans
  • Incidence
  • Mass Screening
  • Odds Ratio
  • Predictive Value of Tests
  • Pregnancy
  • Pregnancy Outcome*
  • Pregnancy Trimester, Second
  • Pregnancy, High-Risk*
  • Prenatal Care
  • Probability
  • Prospective Studies
  • Risk Assessment

Substances

  • Blood Glucose