NICE guidelines (2008) recommend that patients with gestational diabetes (GDM) should no longer have post-partum review with glucose tolerance test (GTT), but that fasting blood glucose is sufficient. We have undertaken a retrospective study of post-partum GTT in patients with GDM, to examine whether the 2 hour glucose value adds useful additional information. Notes of 208 patients with GDM in 20032008 were reviewed, and the results of post-partum GTT were collected. 175 patients had a normal post-partum GTT. In those with abnormal results, 9 patients with previously unrecognised diabetes mellitus were identified by WHO criteria; 2 of these patients had normal fasting glucose but a 2 hour value indicating diabetes. In addition, 14 patients had a normal fasting glucose but elevated glucose at 2 hours. 7 patients had impaired fasting glucose (IFG), but a normal 2 hour value and 3 had both IFG and IGT. If NICE guidance had been followed, 2 patients with diabetes and 14 patients with IGT would not have been identified, leading to different advice and follow up. The 2 patients with diabetes may not have been easily predicted. One was 32 yrs, 60 kg, had diet controlled diabetes through pregnancy, and had previous GDM with a family history of diabetes. The other was 41 yrs, 67 kg, had no GDM in previous 2 pregnancies, required treatment with insulin during pregnancy and had no family history of diabetes. Although there is a cost saving in avoiding GTT in the 175 normal patients, our approach has identified 2 patients with diabetes and allowed advice to be given to reduce the risk of developing diabetes in 14 others. Further work is required to improve the method for identifying those important but uncommon patients who have persistent diabetes or IGT after GDM.
Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.