Objective:To analyze the relationship between rapid plasma regain (RPR) titer of syphilis and adverse pregnancy outcomes in pregnant women and RPR positive rate of newborns. Methods:From Jan 1,2009 to Fab 1,2014,192 pregnant women with syphilis were screened by RPR test and treponema pallidum particle agglutination (TPPA) test before delivery and some of the newborn were screened for peripheral blood at birth and 6 months,so that to find the relationship between RPR titer of syphilis in pregnant women and RPR positive rate and negative conversion rate of the newborns,as well as the adverse pregnant outcomes in pregnant women with syphilis. Results:RPR titer of newborns was closely relative to their mothers. When RPR titer of pregnant women was 1∶1 and 1∶2,PRP positive rate of the newborns was 68.4% and 87.0%,respectively. When RPR titer of pregnant women was higher than 1∶8,PRP positive rate of the newborns reached 100% and higher than those with mother′s RPR titer was ≤1∶4 (P < 0.05). When RPR titer of pregnant women was ≥1∶8,the RPR negative conversion rate of the 6-month newborns was decreased,compared that with mother＇s RPR titer was ≤1∶4(P < 0.05). With the rise of RPR titer of pregnant woman,risk of malformation,stillbirth,preterm birth,congenital syphilis,neonatal death and adverse newborn outcome increased. Preterm birth,congenital syphilis and neonatal malformation rates were increased when RPR titer of pregnant women was ≥1∶8,compared that when RPR titer of pregnant women was ≤1∶4(P < 0.05). Conclusion:With the increase of RPR titer syphilis in pregnant women,PRP positive rate of the newborns was also increased. In addition,when RPR titer of pregnant women was ≥1∶8,PRP positive rate of the newborn reached 100%,the RPR negative conversion rate of the 6-month newborns was decreased, and occurrence rates of malformation,preterm birth and congenital syphilis were significantly increased.