Article title: Study of Relation between Physical Activity and Preterm Birth

Preterm birth is the main cause of neonatal mortality and morbidity and the importance of knowing its causes is clear. Since the effect of physical activity on preterm birth is unknown and its prevention is the priority in health care, we decided to do this study with the aim of determining the relation between physical activity and preterm birth. In this case-control study, 300 pregnant women delivering in Izadi Hospital in Qom, Iran in the second half of 2008, selected through simple sampling. The data were collected using standard pregnancy physical activity questionnaire that categorizes the physical activity into 4 groups: work activities, home activities, transport activities and fun/exercise activities. The physical activity severity was calculated as MET (Metabolic Equivalence Test). Finally, the data were analyzed using descriptive and analytic (x2 and t test) statistics. A p<0.05 was considered as significant. The findings didnt show any significant relation between physical activity and preterm birth. In addition, in view of activity type, fun/exercise and work activities (respectively) and in view of activity severity, sedentary and moderate activities (respectively) were associated with higher, but insignificant rate of preterm birth. Among demographic factors, only gravidity of women was significantly associated with preterm birth. Although, in this study the significant relation between physical activity and preterm delivery wasnt observed, the same research with further sample is recommended.