Abstract： Objective To investigate the jeopardize of Chlamydia trachomatis(CT) infection on mothers and infants during pregnancy in order to find a strategy to deal with.Methods The case history 600 women at different pregnant stages were retrospectively studied from Fed 2003 to Jul 2006 in our hospital,PCR was used to detect cervix uter CT and gerum of child.Results The positive rate of pregnant women's cervical CT infection was 25.5%.There were significant differences in occurrence rate of premature rupture of membrance,neonatal pneumonia between positive and negative groups.Conclusion cervical CT infection in pregnancy has harmful effects on pregnant women and newbern babies,Early diagnosis and treatments of CT infections is important to eugenics.