Need to talk? Call 1800 882 436.
It's a free call with a maternal child health nurse. *call charges may apply from your mobile

Is it an emergency? Dial 000
If you need urgent medical help, call triple zero immediately.

beginning of content

STIs and pregnancy

9-minute read

Key facts

  • Sexually transmitted infections (STIs) are infections that can be passed on during sexual activity.
  • When you are pregnant, STIs can also be transmitted from you to your unborn baby.
  • If left untreated, STIs can also affect your fertility.
  • Most people are tested for STIs when they are planning a pregnancy or first become pregnant.
  • If you think you may have an STI, see your doctor for an STI check, because it’s best to treat an STI early and reduce your risk of complications.

What is an STI?

Sexually transmitted infections (STIs) are infections that can be passed on during sexual activity. If you are pregnant, STIs can also be transmitted from you to your unborn baby. If left untreated, STIs can cause serious problems for both you and your baby.

What causes STIs?

STIs are caused by microorganisms such as bacteria, viruses and parasites, and are sometimes called sexually transmitted diseases (STDs). These organisms can pass between people in semen, blood or vaginal and other bodily fluids.

Many STIs can also be transmitted by:

  • close skin-to-skin contact (for example, during foreplay)
  • blood-to-blood contact
  • sharing needles and other equipment for intravenous (IV) drug use

STIs can also be passed from you to your baby during pregnancy and childbirth.

What are the different types of STIs?

There are many different types of STIs. The most common STIs in Australia are:

There are also other infections that, while not strictly classified as STIs, may be linked with sexual activity, such as:

What are the symptoms of STIs?

Many people with STIs have no symptoms. You might not even know you have an STI until it causes complications, or a sexual partner is diagnosed.

Some people get symptoms such as:

If you have one or more of these symptoms, it doesn’t necessarily mean you have an STI. But it’s still a good idea to see your doctor for a check-up.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

Can having an STI affect my pregnancy?

STIs can affect your ability to become pregnant (your fertility), as well as your pregnancy. Pregnancy doesn’t prevent you getting an STI. If you are infected with an STI while you’re pregnant, it can cause serious problems for you and your developing baby.

If you are pregnant, or wanting to become pregnant, you should ask your doctor to test you for STIs, even if you have tested in the past. If you have concerns about this, discuss them with your doctor, or a health professional at your local sexual health clinic.

If you do catch an STI while you’re pregnant, getting early treatment can reduce the risks. Even if the STI can’t be cured, there are things that can be done to protect you and your baby.

How can STIs affect my baby?

Some STIs, such as syphilis and HIV, can infect a baby still while you’re pregnant. Others, such as chlamydia and genital herpes, can infect the baby during labour and/or birth.

STIs can pose significant health risks to unborn babies. These include:

Getting regular medical care during your pregnancy and discussing any concerns you have regarding STIs with your doctor or midwife help reduce the risk of problems caused by STIs during your pregnancy.

How are STIs diagnosed and treated?

Untreated STIs stay active in the body and may be passed on to sexual partners, or your baby, without you being aware. Therefore, it’s important to get tested if you think you may have an STI.

Having a test for STIs is simple. The type of test depends on the STI, but tests usually involve providing a urine sample, a swab, a blood test or having a physical examination. If the test shows you have an STI, you may need further tests and treatment.

STIs caused by bacteria, such as chlamydia, can usually be treated with antibiotics. Other STIs, such as those caused by viruses (for example, herpes) are not always curable, but there may be things you can do to relieve your symptoms.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

Will I be tested for STIs during pregnancy?

Most people will be offered routine tests for some STIs at their first antenatal care appointment, including:

Depending on your age and circumstances, your doctor may recommend testing for other STIs as well.

What can I do to avoid getting an STI?

Other than not having sex with a partner who could potentially have an STI, practicing safe sex with condoms (used during penetrative sex) and dental dams (used during oral sex) offers the best protection from STIs.

Other ways to avoid STIs are:

  • having sex with one uninfected partner
  • limiting the number of sexual partners you have sex with
  • avoiding sex with a new partner until you’ve both been tested for STIs
  • getting vaccinated against HPV and hepatitis
  • not taking drugs or drinking excessive alcohol (often associated with risk-taking behaviour)

If you are male, getting circumcised reduces your chances of catching some STIs too.

Resources and support

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: February 2023


Back To Top

Need more information?

Condoms and Contraception

Contraception is a way to prevent pregnancy. Using condoms can prevent pregnancy and can also protect you against getting a sexually transmitted infection (STI).

Read more on WA Health website

Safer sex

Safer sex means not allowing your partner's body fluids (blood, semen, vaginal fluids) into your body and vice versa

Read more on WA Health website

STIs and Symptoms | NT.GOV.AU

Most STIs have no symptoms but they can lead to serious long-term health issues if left untreated.

Read more on NT Health website

STI screening | MSI Australia

Information Sheet STI screening. This page is an accessible HTML version of the document shown below.

Read more on MSI Australia website

Sexual Health Information | 1800 My Options

Learn about sexual health, including STI prevention, testing, and treatment. Access reliable information and resources.

Read more on 1800 My Options website

Thrush | SA Health

Thrush or Candidiasis is a common vaginal infection, caused by an overgrowth of yeasts and is not considered to be a sexually transmitted infection

Read more on SA Health website

Sexually Transmitted Infections (STIs) | 1800 My Options

Get information on sexually transmitted infections (STIs) with 1800 My Options. Learn about prevention, symptoms, and treatment options to maintain your sexual health and well-being.

Read more on 1800 My Options website

Chlamydia and pregnancy

Chlamydia is a sexually transmitted infection (STI) affecting both males and females. Chlamydia can cause complications in pregnancy.

Read more on Pregnancy, Birth & Baby website

Trichomoniasis - Better Health Channel

Trichomoniasis during pregnancy may lead to low birth weight babies and prematurity.

Read more on Better Health Channel website

Genital herpes and pregnancy | Health and wellbeing | Queensland Government

If you are pregnant and you get genital herpes, it is important to tell your midwife or obstetrician.

Read more on Queensland Health website

Call us and speak to a Maternal Child Health Nurse for personal advice and guidance.

Need further advice or guidance from our maternal child health nurses?

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.

This information is for your general information and use only and is not intended to be used as medical advice and should not be used to diagnose, treat, cure or prevent any medical condition, nor should it be used for therapeutic purposes.

The information is not a substitute for independent professional advice and should not be used as an alternative to professional health care. If you have a particular medical problem, please consult a healthcare professional.

Except as permitted under the Copyright Act 1968, this publication or any part of it may not be reproduced, altered, adapted, stored and/or distributed in any form or by any means without the prior written permission of Healthdirect Australia.