chlamydia infection is caused by the bacterium chlamydia trachomatis. it is spread during vaginal anal or possibly oral sex with an infected partner. a pregnant woman may spread the infection to her newborn during delivery. you can spread chlamydia even if you do not have symptoms of infection. you can spread the infection until you have been treated. webmd medical reference from healthwise this information is not intended to replace the advice of a doctor. healthwise disclaims any liability for the decisions you make based on this information. © 1995-2011 healthwise incorporated. healthwise healthwise for every health decision and the healthwise logo are trademarks of healthwise incorporated.
what causes chlamydia?