Objective: This study was performed to determine the prevalence and risk factors of low birth weight (LBW) among the live born neonates at the hospitals in Tehran from Sep 2005 till Sep 2006.
Material & Methods: This study was a cross-sectional study. Ten hospitals in Tehran were chosen randomly. During the period of study several days in a month were chosen randomly and all newborns born on those days were assessed. The studied characteristics included sex, gestational age, birth order, the interval to previous birth, existence of congenital anomalies, multiple pregnancy, maternal age, gravidity and parity number, history of maternal fertility (including previous LBW infants, infertility, abortion), history of recent pregnancy (including smoking, drug consumption, x-ray exposure, weight gain, vaginal bleeding, gestational illness, folate and iron consumption, gestational infection), chronic illness of the mother, maternal education and maternal job.
Findings: We studied 514 (56.5%) females and 391 (43.5%) males. The LBW prevalence was 8.6% (78 newborns). There was significant statistical relationship between LBW and gestational age, the interval to previous birth, existence of congenital anomalies, multiple pregnancy, maternal age, history of maternal fertility (including previous LBW infants, infertility, abortion), history of recent pregnancy (including smoking, drug consumption, weight gain, vaginal bleeding, gestational illness, iron consumption, gestational infection), chronic illness of the mother and maternal education.Conclusion: Although our results regarding LBW prevalence and risk factors confirm the results of other studies, we recommend perspective studies to reconfirm the LBW risk factors.