Impact of changes to national UK Guidance on testing for gestational diabetes screening during a pandemic: a single centre observational study.

Van De L'Isle, Yolande; Steer, Philip J; Watt Coote, Ingrid; Cauldwell, Matthew

OBJECTIVE To examine the differences in detection rate for gestational diabetes(GDM) comparing the methodology recommended by the National Institute for Health and Clinical Excellence (NICE) compared with testing described as appropriate during the Covid-19 pandemic by the Royal College of Obstetricians and Gynaecologists (RCOG). DESIGN Cohort study of women delivering between January 1st 2016 and 1st July 2020. SETTING London Teaching Hospital POPULATION: All women delivering between January 1st 2016 and 13th May 2020 and follow-up of women screening negative between 1st April 2020 and 13th May 2020. METHODS Retrospective study of prospectively collected data. MAIN OUTCOME MEASURES Detection rate of gestational diabetes. RESULTS Using the RCOG guidance, the overall rate of women identified as having gestational diabetes fell from 7.7% (1853/24168) to 4.2% (35/831)(p=0.0003). Of 230 women who tested negative according to the RCOG criteria from April 1st to May 13th but who subsequently had an oral glucose tolerance test, 47 (20.4%) were diagnosed as having gestational diabetes according to the NICE criteria. CONCLUSIONS In our setting, The RCOG Covid-19 gestational diabetes screening regime failed to detect 47 of 82 (57%) women subsequently identified as gestational diabetics, and therefore cannot be recommended for general use.