Results
The mean (SD) percentage of women diagnosed with GDM was 14.78 (2.24) in summer (June, July, August) compared with 11.23 (1.62) in winter (p < 0.001), 12.13 (1.94) in spring (p = 0.002), and 11.88 (2.67) in autumn (p = 0.003). There was a highly significant positive correlation of the percentage testing positive for GDM with the mean maximum monthly temperature (R2 = 0.248, p < 0.001). There was a statistically significant 33.8% increase in the proportion of GDM diagnoses from June 2020 onwards, possibly related to a reduction in exercise secondary to the Covid-19 pandemic.