Seasonal change in the incidence of preeclampsia in Zimbabwe

Background The aim of our study was to evaluate the number of women with hypertensive complications during pregnancy in a southern province in Zimbabwe and to examine the annual change in the incidence of preeclampsia. Methods. In three different hospitals the preeclamptic women who were treated between January 1992 and August 1995 were counted. This data was compared with the amount of rainfall obtained from the local meteorological stations. Results. A distinctive change in the incidence of preeclampsia during the year could be observed. These changes go along with the seasonal variation in precipitation: at the end of the dry season and in the first months of the rainy season there is an increase in the incidence. Conclusions. The relationship between climate and occurrence of preeclampsia raises new questions in the pathophysiology of preeclampsia. Possible explanations could be the impact of humidity and temperature on vessels or the production of vasoactive substances. Dry and rainy seasons influence the agricultural yields and therefore the nutritional status could also play a role in the pathophysiology.