Gestational glucose intolerance is detected during pregnancy with the glucose tolerance test (GTT). This test is usually recommended around 24-28 weeks, and may be repeated around 32-34 weeks in mothers with high-risk pregnancies.
By identifying gestational glucose intolerance during pregnancy, the mother can alter her diet to keep her blood sugar from getting too high. Gestational glucose intolerance is more common in overweight women, older women, those with a family history of diabetes, or women who have previously delivered a baby weighing more than nine pounds.
The GTT is done at your doctor’s office. You drink a glass of sweet liquid called glucola (it tastes like sweetened Coke or Pepsi) on an empty stomach, and then your blood sugar is checked one hour later. (An alternative to drinking the sugar-loaded liquid is to measure the blood sugar 1-2 hours after a big meal.) The result of the GTT should be available within a few hours. After ingesting the test “meal,” it’s important to stay active (e.g. walking) so your body has a better chance of metabolizing the sugar load than if you just sit there waiting to have your blood drawn.
If this one-hour screening test turns out to show high blood sugar, the doctor may recommend a more accurate three-hour test. Only around 15 percent of women with abnormal one-hour GTT will have an abnormal three-hour GTT test. If the three-hour test is abnormal, the doctor may recommend a diabetic diet throughout the rest of pregnancy. New research questions the value of routine screening for gestational glucose intolerance. A 1990 study of 1,307 women (533 of whom were not screened and 774 who were screened) showed that screening resulted in more tests and worry during pregnancy and a significantly higher cesarean rate in the screened mothers, but it did not decrease the number of large infants. These researchers concluded that the routine use of GTT caused more worry than the benefits derived. Discuss with your practitioner whether or not the GTT is necessary in your particular pregnancy.