If you get Chlamydia but don’t get treated, it can spread to other parts of your body.
Women can get pelvic inflammatory disease which can cause long-term pain in your pelvic area or abdomen.
You can also end up with damaged or blocked fallopian tubes (the tubes that carry eggs from your ovaries to your womb every month). This will make it hard or impossible to get pregnant, or may cause an ectopic pregnancy, which is when a pregnancy occurs outside your womb. An ectopic pregnancy can be very serious.
Men can get a painful infection in their testicles and find it harder to have children as it affects their fertility.