The study revealed that there can be 51 per cent rise in the incidence of the high blood sugar condition due to a possible peak in the temperature. The study examined seasonal patterns in glucose tolerance and in the diagnosis of gestational diabetes mellitus -- a form of high blood sugar affecting pregnant women. The results indicated that the summer months (June-August) were associated with an increased glucose level and a 51 per cent (or 1.5 times) increased frequency of gestational diabetes compared with the other seasons.