Gestational diabetes mellitus (GDM; approximately 5% of pregnancies) represents the most important risk factor for development of later-onset diabetes mellitus. We examined concordance between GDM diagnosis defi ned using the original 1999 World Health Organization (WHO) criteria and the more recent 2013 WHO criteria and 2015 National Institute for Health and Care Excellence (NICE) criteria. We studied two groups: a case-control group of 257 GDM positive and 266 GDM negative cases, and an incident cohort 699 GDM positive and 6,231 GDM negative cases. In the incident cohort, GDM prevalence was 3.7% (WHO 1999 criteria), 11.4% (NICE 2015 criteria) and 13.7% (WHO 2013 criteria). Our results showed that a signifi cant number of additional cases are detected using the more recent NICE and WHO criteria than the original 1999 WHO criteria, but these additional cases represent an intermediate group with 'moderate' dysglycaemia (abnormal blood glucose levels). Our results also show that use of these newer criteria misses a similar group of intermediate cases that were defi ned as GDM by the 1999 WHO criteria and that glycated haemoglobin in isolation is unlikely to replace the oral glucose tolerance test in GDM diagnosis.

BackgroundWomen with gestational diabetes (GDM) have an elevated risk of developing type 2 diabetes (T2DM). NICE Guidance recommends women who develop GDM are screened 6 weeks post-partum and annually thereafter.AimTo evaluate conformity to guidance of screening in women with GDM by 6-week post-partum fasting plasma glucose (FPG) and annual FPG and determine time between delivery and development of T2DM.MethodRecords at a tertiary referral centre were used to identify women (n = 54) diagnosed with GDM by antenatal oral glucose tolerance test between July 1999 and January 2007. Data from laboratory records were used to collect investigations of glycaemic status during the follow-up period (median follow-up 12.4 years, range 9.5–17.1 years).ResultsOf 252 women, 102 (40.2%) did not have a FPG at 6 weeks (+/−2 weeks). Of these, median time to first test was 1.2 years (range 0.04–10.8 years), with only 43.1% followed-up within 1 year. In those who had a 6-week FPG, 17 (11.3%) women had no further tests. A total of 84 (33% of those with gestational diabetes in the index pregnancy) women were diagnosed with T2DM; median time from delivery to diagnosis was 5.2 years (range 0.35–15.95). We found the only significant factor for a follow-up test at 1-year post-partum was the use of insulin.ConclusionOur data suggest an alternative approach is needed for monitoring women with a history of GDM. This needs to be appropriate for a generally healthy group in which traditional screening mechanisms may not be adequate or sufficient.