Chlamydia is the most commonly diagnosed sexually transmitted infection (STI) in New Zealand. It affects both men and women. Most people that have chlamydia don't show any symptoms – but they can still infect other people. Chlamydia can be easily treated with antibiotics. Left untreated, chlamydia can cause infertility.

How is chlamydia spread?

In nearly all cases chlamydia is transmitted through sexual contact.

  • You can get chlamydia by having unprotected 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). 
  • Chlamydia can also be spread through other sexual practices such as mutual masturbation or fingering.
  • One simple way to protect yourself is by using a condom when engaging in sexual intercourse.

Another way of transmitting the infection is from mother to baby during birth. If this occurs, the baby may develop an eye or lung infection. This needs urgent treatment.

If you are sexually active, it is important to have regular STI checks. If you think you may have been exposed to chlamydia, see your doctor for an additional STI check.

What are the symptoms of chlamydia?

Most people who are infected by chlamydia don't notice any symptoms and so do not know they have it.

  • If you do have symptoms, they may not appear until a few weeks after you have sex with an infected partner. Symptoms can appear 1 to 3 weeks after infection, many months later, or not until the infection has spread to other parts of your body.
  • Chlamydia can be transmitted to other people even if you don't have symptoms.
  • If you have infection but no symptoms, you can remain infectious for months or even years without knowing it.

Common symptoms, if they do occur, may include:

Women Men
  • unusual vaginal discharge
  • unusual vaginal bleeding (especially after sex)
  • lower abdominal pain (including pain during sexual intercourse)
  • discomfort when passing urine
  • rectal discharge or discomfort.
  • soreness or redness at the opening of the penis
  • discomfort when passing urine
  • clear or whitish discharge from the penis
  • rectal discharge or discomfort.

Chlamydial infection of the throat may occur, but is uncommon and usually does not cause any symptoms.

How is chlamydia diagnosed?

The best way to find out if you have chlamydia is to have a sexual health check-up.

  • Women need to have an examination if a full check-up is being done but sometimes just a urine sample is enough.
  • Men need to give a urine sample to test for chlamydia. If rectal infection is suspected, a swab is taken from just inside the anus (bottom).

How is chlamydia treated?

Chlamydia is easily treated with antibiotics such as with doxycycline which is taken as a course of treatment over 7 days, or with azithromycin which is a single-dose treatment.

It is important to finish all the antibiotics, otherwise the infection may not be properly treated.

Condom use during the treatment period

  • Avoid having sexual intercourse without a condom during treatment because the infection can still be transmitted, or use condoms for 7 days after the start of treatment, and until 7 days after all current sexual partner(s) have been treated.
  • If you are using a combined oral contraceptive pill use a condom for 14 days when having sex, as antibiotics can affect the reliability of the contraceptive pill.

After completing the treatment, phone your doctor or return to the clinic for a follow-up check after 3 months to check you have not been re-infected.

Do sexual partners need treatment?

If you have had sex without a condom with your sexual partner(s) it is very likely they are infected with chlamydia. This means it is important they have a sexual health check-up and be treated for chlamydia regardless of symptoms or test results.

Why is treatment of chlamydia important?

When treated early, chlamydia does not cause any long-term complications. Left untreated, serious and permanent damage can occur.


If left untreated, chlamydia may lead to pelvic inflammatory disease (PID). This is when the reproductive organs, found in the pelvis, become inflamed. PID may cause ectopic pregnancies (the pregnancy develops in the fallopian tubes instead of the uterus), infertility (when the fallopian tubes become damaged by scar tissue preventing further pregnancy) or chronic pelvic pain.


If not treated, chlamydia can spread to the testicles, leading to pain and swelling. Chlamydia may occasionally cause infertility in men. Sometimes chlamydia may trigger a condition called Reiter's disease (or 'sexually acquired reactive arthritis') which causes inflammation of the eyes, skin and joints.


Chlamydia can be passed from mother to baby during birth. The baby may subsequently develop eye and/or ear infections, or pneumonia.

How can I prevent getting chlamydia?

Anyone who is sexually active can catch chlamydia. You're most at risk if you have a new sexual partner or don't use a barrier method of contraception, such as a condom, when having sex. You can help to prevent the spread of chlamydia by:

  • using a condom every time you have vaginal or anal sex
  • using a condom to cover the penis during oral sex
  • using a dam (a piece of thin, soft plastic or latex) to cover the female genitals during oral sex or when rubbing female genitals together.
  • not sharing sex toys.

If you do share sex toys, wash them or cover them with a new condom between each person who uses them.

Learn more

The following links provide further information on chlamydia. Be aware that websites from other countries may contain information that differs from New Zealand recommendations.

Chlamydia Sexual Health Society (NZ)
Chlamydia Ministry of Health (NZ)
Chlamydia Family Planning NZ
Chlamydia NHS Choices (UK)


  1. Chlamydia guideline Sexual Health Society (NZ)
  2. Treatment of sexually transmitted and other genital infections BPAC (NZ)
Credits: Editorial team. Last reviewed: 01 Sep 2013