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.