METEOROLOGICAL EFFECTS ON DAILY BIRTH FREQUENCY AND GESTATIONAL LENGTH IN BARNAUL, SOUTH-WEST SIBERIA
In order to verify possible environmental predictors of labor onset in severely continental climate by means of correlation, multi regression and dispersion analysis we studied associations between daily number of births, gestational length and meteorological factors during the year of 1998 in Barnaul city, south-western Siberia. The medical records of 1 154 pregnant women aged 15-43 who gave births to single fetuses of both sexes were analyzed. The weak correlations were stated between atmospheric temperature, pressure gradient and daily number of births: its daily frequency grew in days with high temperature and sharp decrease of pressure by means of labor with decreased gestation length especially in January and February, the period of Siberian anticyclone. No associations were found with relative air humidity, wind velocity, and oxygen air concentration. The major role of atmospheric pressure was suggested among the external factors additionally influencing internal causes for labor initiation. Possible physiological mechanisms of pressure influences on human body are discussed.