You can get chlamydia by having vaginal, anal, or oral sex with someone who has chlamydia.

If your sex partner is male you can still get chlamydia even if he does not ejaculate (cum).

If you’ve had chlamydia and were treated in the past, you can still get infected again. This can happen if you have unprotected sex with someone who has chlamydia. If you are pregnant, you can give chlamydia to your baby during childbirth.

The only way to avoid STDs is to not have vaginal, anal, or oral sex.

If you are sexually active, you can do the following things to lower your chances of getting chlamydia:

Be in a long-term mutually monogamous relationship with a partner who has been tested and has negative STD test results;

Use latex condoms the right way every time you have sex.

Anyone who has sex can get chlamydia through unprotected vaginal, anal, or oral sex. However, sexually active young people are at a higher risk of getting chlamydia. This is due to behaviors and biological factors common among young people. Gay, bisexual, and other men who have sex with men are also at risk since chlamydia can spread through oral and anal sex.
Have an honest and open talk with your health care provider. Ask whether you should be tested for chlamydia or other STDs. If you are a sexually active woman younger than 25 years, you should get a test for chlamydia every year. If you are an older woman with risk factors such as new or multiple sex partners, or a sex partner who has an STD, you should get a test for chlamydia every year. Gay, bisexual, and other men who have sex with men; as well as pregnant women should also get tested for chlamydia.

Most people who have chlamydia have no symptoms. If you do have symptoms, they may not appear until several weeks after you have sex with an infected partner. Even when chlamydia causes no symptoms, it can damage your reproductive system.

An abnormal vaginal discharge;

A burning sensation when urinating.

A discharge from their penis;

A burning sensation when urinating;

Pain and swelling in one or both testicles (although this is less common).

Rectal pain

Discharge

Bleeding

You should be examined by your doctor if you notice any of these symptoms or if your partner has an STD or symptoms of an STD. STD symptoms can include an unusual sore, a smelly discharge, burning when urinating, or bleeding between periods.

Laboratory tests can diagnose chlamydia. Your health care provider may ask you to provide a urine sample or may use (or ask you to use) a cotton swab to get a sample from your vagina to test for chlamydia.

You should not have sex again until you and your sex partner(s) have completed treatment. If your doctor prescribes a single dose of medication, you should wait seven days after taking the medicine before having sex. If your doctor prescribes a medicine for you to take for seven days, you should wait until you have taken all of the doses before having sex.

The initial damage that chlamydia causes often goes unnoticed. However, chlamydia can lead to serious health problems.
If you are a woman, untreated chlamydia can spread to your uterus and fallopian tubes (tubes that carry fertilized eggs from the ovaries to the uterus). This can cause pelvic inflammatory disease (PID). PID often has no symptoms, however some women may have abdominal and pelvic pain. Even if it doesn’t cause symptoms initially, PID can cause permanent damage to your reproductive system. PID can lead to long-term pelvic pain, inability to get pregnant, and potentially deadly ectopic pregnancy (pregnancy outside the uterus).
Men rarely have health problems linked to chlamydia. Infection sometimes spreads to the tube that carries sperm from the testicles, causing pain and fever. Rarely, chlamydia can prevent a man from being able to have children.
Untreated chlamydia may also increase your chances of getting or giving HIV – the virus that causes AIDS.