Abstract: ObjectiveTo investigate the incidence and risk factors of low birth weight(LBW)in Changzhou city, Jiangsu province.MethodsWith cluster random sampling method,in fants born from Jan 1st, 2006 to Dec 31 st, 2008 and their parents from urban and rural areas were enrolled in the survey.ResultsTotally 6 225 persons were enrolled,with 3252 boys(52.24%)and 2 973 girls(47.76%).The incidence of low birth weight was 2.36% (147 cases)The rates of abnormity and death in the low birth weight group were 2.04% and 4.76%,respectively,which were higher than those of normal group(0.11% and 0.28%,respectively,P<0.001).Compared to the normal group,the odds ratios(95% confidence in terval)of abnormity and deathrate in low birth weight group were 15.92(4.08-62.2)and 17.80(7.15-44.4),respectively.Multifactor logistic regression analysis showed that the related factors of LBW in the boys were parity and premature birth and those in the girls were parity,premature birth,pregnancy hypertension,and induced abortion.ConclusionLow birth weight is one of important risk factors causing abnormity and death of infants in Changzhou.Parity,premature birth, pregnancy hypertension,and induced abortion are important risk factors for low birth weight in Changzhou city.Pregnancy hypertension and induced abortion have severe impact on LBW of girl than that of of boys.