Secondary outcome: Analyses of CGM data
Data from the CGM was extracted for use with a minimum wear-time of 7 out of 14 days (50% of data captured) at four timepoints during pregnancy: first trimester (9-13 weeks gestation), early second trimester (18—23 weeks), late-second to early-third (24-28 weeks) gestation) and third trimester (32-33 weeks of gestation). The following variables were calculated from CGM readings for each participant: Percentage time-in-range (% TIR), percentage time-above-range (% TAR), percentage time-below-range (% TBR), mean glucose, standard deviation (SD), percentage coefficient of variation (%CV) and mean amplitude of glycaemic excursion (MAGE). The % of time in target ranges were defined as: %TIR (3.5–7.8 mmol/L), %TAR (>7.8mmol/L, and %TBR (<3.5mmol/L) and were used to assess glycaemic control 11. MAGE, quantifies major swings of glycaemia and excludes minor ones was and is considered the gold standard for assessing intra-day glycaemic variability 19, along with SD and %CV. Extracted CGM data was used to calculate mean glucose, SD, %CV and MAGE, by an automated Software EasyGV version 9.0.R2.