||Abnormal carbohydrate metabolism frequently first appears in women during pregnancy as a transient condition. This form of latent diabetes mellitus is termed gestational diabetes. Diabetes is pregnancy, either overt or gestational, poses an increased risk to both mother and fetus. Fortunately such risks have been greatly reduced by advances in the treatment of this complication. Obviously, the implementation and the effectiveness of special antenatal care is dependent on an accurate and early diagnosis. However, the identification of gestational diabetics is inherently difficult because these women frequently lack the clinical symptoms and signs associated with overt diabetes mellitus. The purpose of this study was to examine the effectiveness of a one-hour blood sugar test as a method to detect gestational diabetes, and to compare its effectiveness to that of the more commonly used screening criteria - family history of diabetes, previous large infant, previous poor obstetrical history, and maternal obesity. In addition, maternal age and parity was examined to determine their usefulness in predicting the development of gestational diabetes. This retrospective study was based on an examination of the medical records of 630 women, 531 of whom were administered a one-hour blood sugar test in addition to being screened for gestational diabetes by traditional methods. Seven gestational diabetics were identified through the use of a one-hour glucose screening test, and five of these seven prenatal patients also had traditional screening factors present. The remaining two patients representing 29 percent of the gestational diabetics were identified solely by the one-hour test. A maternal age of 25 year or more was the only factor which demonstrated a significant association with gestational diabetes. Macrosomia, which was not correlated with gestational diabetes, was however significantly associated with maternal obesity, maternal weight gain of greater than 30 pounds during pregnancy, maternal age of 25 year or more, and a past history of large infants.