Seasonal Variations of Heights, Weights and Head Circumferences of Full term Newborns in Hamadan City, Iran

Backgounds: A number of studies have focused on the effects of season of birth, as an environmental fac-tor, on embryonic development. Methods: In a retrospective descriptive work, heights (crown to heel), weights and head circumferences of the full term, normal, and singleton newborn infants in Hamadan City (west of Iran) were collected from their randomly selected files in Fattemieh Hospital during five consecutive years (1998-2002). The studied files were 1800 cases, about 15% of total live births in the hospital during the considered period. We statistically compared the above parameters in four seasons. Results: Seasonal variation of mean birth weight and mean birth height were not statistically different. How-ever, mean head circumference showed a peak in winter and a decline in autumn with statistical significant (P < 0.005). Conclusion: We can conclude that season of birth can be considered as one of the environmental factors that affect on embryonic development.