This is one of the most common sexually transmitted diseases. Chlamydia is transmitted through sex: vaginal, anal and oral sex, and can be passed on via sex toys. The chlamydia infection is caused by bacteria. Normally asymptomatic, the infection can give rise to symptoms such as vaginal discharge, lower abdominal pain and dysuria. All pregnant women are screened for chlamydia during their first prenatal visit in the US. If you think you may be infected, or if you have any symptoms, tell your midwife or healthcare provider who can schedule a test. The test will be done during a pelvic exam or as a urine sample.
The infection can make its way to the fetal membranes, causing preterm labor. It can also be passed to the baby at birth. Chlamydia is treated with antibiotics, and after treatment, there is no risk that the infection will be transmitted to the fetal membranes or to the baby after birth. You will need to have a test of cure one month after your treatment is finished.
Source: https://www.cdc.gov/std/chlamydia/stdfact-chlamydia.htm