Abstract: Chlamydia trachomatis（CT） is currently the most common sex transmitted disease pathogen world-widely，which is an important reason of lower genital tract infection as well. However，the Chlamydia trachomatis infection is always asymptomatic and the clinicians did not pay adequate attention on it. Also it needs advanced lab equipments and techniques in detecting and screening the population with high risks and the follow-up and treatment is also lack of attention. Women infected with Chlamydia trachomatis suffer from the damages of the pathogen itself and the immune reactions it caused，such as miscarriage，fetal growth restriction，fetal distress，pre-rupture of membrane，preterm labour，low body weight neonate，still birth，intra-uterine infection，infection of neonate and the puerperal infection and post partum haemorrage. So purposeful screening and treatment towards Chlamydia trachomatis infection are important to reduce the complications of both maternal and fetal.

Key words: Chlamydia trachomatis, Pregn, Fetal membranes, premature rupture, Chorioamnionitis