An observational study comparing 2-hour 75-g oral glucose tolerance with fasting plasma glucose in pregnant women: both poorly predictive of birth weight.
The definition and treatment of glucose intolerance during pregnancy are matters of intense controversy. Our goal was to examine the value of the 75-g oral glucose tolerance test (OGTT) in terms of its ability to predict birth weight percentile in a group of women with singleton pregnancies who received minimal treatment for their glucose intolerance.
We reviewed the results of OGTTs performed between 24 and 28 weeks' gestation in a group of 300 consecutive high-risk women (mean age 29.5 years [95% confidence interval, CI, 28.9-30.1]; parity 1.5 [95% CI 1.4-1.7]) whose plasma glucose level 1 hour after a randomly administered 50-g glucose load was 8.0 mmol/L or above. These data were compared with results for a randomly selected control group of 300 women whose plasma glucose level 1 hour after a 50-g glucose load was less than 8.0 mmol/L (mean age 28.0 years [95% CI 27.4-28.6]; parity 1.5 [95% CI 1.3-1.6]).
For 76 (25.3%) of the 300 high-risk women, the plasma glucose level 2 hours after a 75-g glucose load (confirmatory OGTT) was 7.8 mmol/L or more, but only 6 of these were treated with insulin, which emphasizes the low level of intervention in this group. Thirty (10.0%) of the neonates in this group were large for gestational age (LGA; adjusted weight at or above the 90th percentile). This proportion did not significantly differ from the proportion for the control group (25 or 8.3%). After exclusion of the 6 insulin-treated women, simple correlations between birth weight percentile and fasting or 2-hour plasma glucose levels were very weak (r = 0.23 and 0.16 respectively; p
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Cites: Am J Obstet Gynecol. 1990 Jul;163(1 Pt 1):86-922375375