terialisation of the peripheral blood with increasing temperatures.
In 2016, another Australian study, using the current ADIPS criteria, found a marked increase in the prevalence of GDM in the summer compared with the winter seasons. 4 These observations have subsequently been found, reported, and confirmed in many parts of the world 5-7 although there have been some negative outcomes. 8 Many of these studies relate to the increasing prevalence of GDM in the summer months with climate change, although to our knowledge, this aspect has not been specifically examined.
What has not been systematically examined is whether these changes are acute and related to the temperature of the day, the temperature of the pathology collection centre, or whether it is a seasonal factor, perhaps related to the accumulation of brown fat and changes in insulin sensitivity. 5 What is known is that the overall prevalence of GDM in most reported studies is higher in summer than in winter -or in hotter rather than colder environs. In Australia, the change in the diagnostic criteria for GDM has resulted in an approximate 50% increase in prevalence 9 and the changed criteria appears to be exacerbating the seasonal variation. Whether the increased and increasing prevalence of GDM occasioned by both these factors is an advantage to the outcome of the pregnancy remains to be determined. In Australia, perhaps standardisation of the temperature in pathology collection areas could be considered. Or perhaps criteria adjustment may be required for different seasons.
Tegan E. van Gemert 1 Robert G. Moses 2 