New International Association of the Diabetes and Pregnancy Study Groups (IADPSG) recommendations for diagnosing gestational diabetes compared with former criteria: a retrospective study on pregnancy outcome

Aims The International Association of the Diabetes and Pregnancy Study Groups (IADPSG) Consensus Panel recommends new criteria for diagnosing gestational diabetes. We evaluated the clinical and metabolic characteristics, and pregnancy outcome, in women previously classifiable as 'normal' according to the 4th International Workshop Conference on gestational diabetes criteria, but reclassified as 'abnormal' according to the new recommendations. Methods Using the new IADPSG criteria, 3953 pregnancies were retrospectively reclassified as 1815 women with normal glucose tolerance and 2138 with gestational diabetes, 112 (2.8%) of whom would have been classified as normal according to the older criteria. Results Of the 2138 women classified as abnormal by the new criteria, the 112 women now reclassified as abnormal were younger and had a lower pre-pregnancy BMI than the 2026 women who had also been classified as abnormal by the previous criteria. The 100-g oral glucose tolerance test showed significantly higher glucose levels in these 112 women than in the 1815 women reclassified as normal (P < 0.0001). Caesarean section was significantly more frequent (P < 0.01) and the ponderal index for the newborn significantly higher in these reclassified women than in those classified as normal (P < 0.0001), and their basal glucose levels correlated significantly with the ponderal index (P < 0.05). Conclusion The new criteria for diagnosing gestational diabetes identified a group of women previously classifiable as normal according to the 4th International Workshop Conference criteria, but revealing metabolic characteristics and pregnancy outcomes resembling those of women who would have been considered to have gestational diabetes by the previous criteria.