Eclampsia: is there a seasonal variation in incidence?

To clarify whether seasonal variation of temperature and humidity has any effect on the incidence of eclampsia. Eclampsia is the second major cause of maternal mortality in Pakistan.

Data was collected monthwise for the year 1996 from 4 large Govt. teaching hospitals of 4 provincial metropolis of Pakistan. Each province has diverse climate with considerable variation of air temperature and humidity.

There were 395 cases of eclampsia amongst 18,483 deliveries in 1996, giving an incidence of 2.14%. In Karachi (Sindh Province) with mild hot and humid climate and mild winter months, there was increase in eclampsia cases from April-July and in September. Otherwise the incidence remained stable. In Rawalpindi (Punjab Province) with moderately hot summer and cold winter, it was highest in hot season from May to September but was stable in winter. In Peshawar (N.W.F.P) and Quetta (Baluchistan Province) with more severe cold and dry winter the incidence peaked in winter and summer months both.

The pattern of eclampsia cases showed variations in extremes of temperature but it was stable in mild weather. However, the statistical analysis revealed non-significant relationship of incidence of eclampsia with temperature when analysed by linear regression analysis.