As chlamydia is a sexually transmitted infection (STI), it is transmitted (passed on) from one person to another during intimate sexual contact. You can catch chlamydia through having:
- unprotected vaginal sex,
- unprotected anal sex,
- unprotected oral sex,
- genital contact with an infected partner, or
- sharing sex toys if they are not washed or covered with a condom each time they are used.
If infected semen or vaginal fluid comes into contact with the eye, it can cause conjunctivitis.
It is not clear whether chlamydia infection can be spread by transferring infected semen or vaginal fluid on the fingers or by rubbing female genitals (vulvas) together.
As it is common for someone with the chlamydia infection not to have symptoms, it is possible for him or her to infect a partner without knowing.
Chlamydia can be passed from a mother to her baby during childbirth. Although no obvious symptoms are immediately apparent, the infection will often develop after birth, and can result in complications such as inflammation and discharge in the baby’s eyes (conjunctivitis) and pneumonia.
