Objective: to examine pregnancy outcomes in relation to different categories of glucose tolerance during pregnancy.
Design: prospective observational cohort study.
Setting: patient recruitment and data collection were performed in four delivery departments in southern Sweden.
Population: women delivering during 2003-2005; 306 with gestational diabetes mellitus, 744 with gestational impaired glucose tolerance and 329 randomly selected controls.
Methods: all women were offered a 75 g oral glucose tolerance test during pregnancy. On the basis of their capillary 2-hour plasma glucose concentrations, three groups were identified: gestational diabetes mellitus (>10.0 mmol/l), gestational impaired glucose tolerance (8.6-9.9 mmol/l) and controls (<8.6 mmol/l). Data for the groups were compared using a population-based database.
Main outcome measures: maternal and fetal outcomes.
Results: for the gestational diabetes mellitus group, adjusted odds ratios (95% confidence intervals) for hypertensive disorders during pregnancy and induction of labor and emergency cesarean section were 2.7 (1.3-5.8), 3.1 (1.8-5.2) and 2.5 (1.5-4.4), respectively; and for Apgar score <7 at 5 minutes, need for neonatal intensive care >1 day and large-for-gestational age infant were 9.6 (1.2-78.0), 5.2 (2.8-9.6) and 2.5 (1.3-5.1), respectively. The increases in odds ratios for the gestational impaired glucose tolerance group were less pronounced but still significant for hypertension during pregnancy, induction of labor, large-for-gestational age infant and use of neonatal intensive care >1 day, with odds ratios (95% confidence interval) 2.0 (1.0-4.1), 1.8 (1.1-3.0), 2.1 (1.1-3.9) and 2.1 (1.1-3.8), respectively.
Conclusions: these data indicate that even limited degrees of maternal hyperglycemia may affect the outcome of pregnancy.