Contraception options: a guide to how they work

Start with what matters in your life. You might want a method you control at the time of sex, remember on a schedule, or use for years after insertion. You may care about hormones, period changes, privacy, STI protection, procedures, cost, breastfeeding, or future pregnancy.

Effectiveness also depends on use. Methods that remain in place, such as an implant or IUD, leave less room for missed tablets or late changes. Pills, condoms, diaphragms, fertility-awareness methods and withdrawal depend more on consistent, correct action. ‘Correct use’ figures assume the method is used exactly as directed; ‘typical use’ reflects what happens in everyday life.

Before changing methods, check when the new method starts protecting against pregnancy. You may need to overlap methods or use condoms for a period so there is no gap. A doctor, nurse or pharmacist can give instructions for the particular method and timing.

Both types are taken daily. Missed-tablet instructions differ between products, so it matters which pill you use.

The combined pill contains oestrogen and progestogen. It mainly prevents ovulation and thickens cervical mucus. Bleeding often becomes lighter, more regular and less painful, and some people use it to skip bleeding. Fertility usually returns quickly after stopping. Possible effects include nausea, breast tenderness, headache, mood or skin changes, and breakthrough bleeding. It also causes a small increase in the risk of blood clots, heart attack and stroke, so it is not suitable for everyone—for example, some people with particular migraines or clotting risks, or people over 35 who smoke.

The progestogen-only pill thickens cervical mucus; some types also stop ovulation. It does not contain oestrogen and can be an option when oestrogen is unsuitable. Irregular bleeding, spotting or no bleeding can occur. Fertility usually returns quickly after stopping. The time allowed for a late or missed tablet differs between types, and vomiting, severe diarrhoea and some medicines can reduce protection, so follow the instructions for your pill.

Neither type protects against STIs.

The vaginal ring releases oestrogen and progestogen and works in a similar way to the combined pill. You insert it into the vagina, leave it in for three weeks, then usually have a ring-free week before inserting a new one. Some regimens use rings continuously under medical guidance.

The ring avoids a daily tablet and is not affected by vomiting or diarrhoea, but it needs changing on schedule. It may make bleeding lighter, more regular and less painful. Fertility usually returns quickly after removal. Side effects and medical restrictions are similar to the combined pill, including a small risk of blood clots, heart attack and stroke. It does not protect against STIs.

The injection contains progestogen and mainly stops ovulation. A doctor or nurse gives it about every three months. It removes the need for daily action, but appointments must stay on schedule and an injection cannot be removed once given.

Bleeding may be irregular or prolonged at first and often becomes lighter or stops over time. Possible effects include headache, mood or skin changes, breast tenderness and weight gain. Bone density can fall slightly during use and generally recovers after stopping. Return to fertility can take several months and, for some people, longer than a year, so this may matter if pregnancy is planned soon. The injection does not protect against STIs.

The implant is a small progestogen-releasing rod placed under the skin of the upper arm by a trained doctor or nurse. It prevents ovulation, thickens cervical mucus and works for up to three years. Insertion and removal use local anaesthetic.

Bleeding changes are common and unpredictable: periods may become lighter, stop, last longer or happen more often. Headache, breast tenderness, mood or skin changes can occur, and some medicines can reduce effectiveness. Rarely, a deeply placed implant needs more involved removal. Fertility usually returns quickly after removal. The implant does not protect against STIs.

An IUD is a small device placed in the uterus by a trained doctor or nurse. Both hormonal and copper IUDs are more than 99% effective at preventing pregnancy in the first year of use and require little ongoing action, but insertion and removal are procedures. Rare risks include the device coming out, perforation of the uterus during insertion, and pelvic infection shortly after insertion, usually where an STI was already present. Fertility returns promptly after removal. Neither type protects against STIs.

Insertion can be painful. Discuss pain-relief options before the appointment, as well as what to expect afterwards and when to seek help.

A hormonal IUD releases progestogen and, depending on the type, works for five to eight years. It thickens cervical mucus and changes the uterine lining. Bleeding and spotting are common during the first months; later, periods often become lighter, less painful or stop. It may suit some people who cannot use oestrogen, although it is not suitable for everyone.

A copper IUD contains no hormones and starts working immediately. Australian devices last for five or ten years, depending on the type. Periods may become heavier, longer or more painful, especially at first, so existing heavy bleeding or low iron may affect the decision. It can also be used as emergency contraception.

External condoms are worn over an erect penis or sex toy. Internal condoms are placed inside the vagina before sex. Both create a barrier that helps prevent semen entering the vagina. They are used each time and do not affect hormones, bleeding or future fertility. Breakage, slipping, late application and incorrect use reduce pregnancy protection.

External and internal condoms also reduce the risk of many STIs when used correctly throughout sex, although they do not cover all genital skin. This STI protection is a separate consideration from pregnancy prevention, and condoms can be used with another contraceptive method.

A diaphragm is a reusable silicone cup placed in the vagina to cover the cervix. It must be used with contraceptive gel, positioned correctly before penis-in-vagina sex and left in for at least six hours afterwards, but no more than 24 hours. A doctor or nurse can check the fit and technique.

The diaphragm contains no hormones and does not change bleeding or delay fertility. It requires action for each episode of sex and may cause irritation or bladder infections in some users. It does not protect against STIs, and access in Australia can be difficult.

Fertility-awareness methods use daily observations—such as cervical mucus, waking temperature and cycle dates—to identify fertile days. On those days, you avoid penis-in-vagina sex or use another method. These approaches contain no hormones and do not alter fertility, but they require training, daily records and agreement about what to do during the fertile window.

Illness, stress, travel, irregular cycles, breastfeeding and the years around menopause can make patterns harder to interpret. Effectiveness varies substantially between specific methods and between correct and typical use; an app that predicts dates from earlier cycles is not necessarily a validated fertility-awareness method. These methods do not protect against STIs.

Withdrawal means removing the penis from the vagina before ejaculation and keeping semen away from the vulva and vaginal opening. It has no medicine side effects, but timing can be difficult and sperm may be present before ejaculation or remain after a recent ejaculation. In typical use it is less reliable than many other methods. It does not protect against STIs.

Breastfeeding alone should not be assumed to prevent pregnancy. LAM is a temporary method only when all three conditions are met: your baby is under six months old; your periods have not returned; and you are fully or almost fully breastfeeding. Its effect becomes less reliable when feeds reduce, night feeds stop, other food or drink is introduced, menstruation returns, or six months have passed. The effect of frequent expressing on LAM is uncertain.

Plan another method before any condition changes. LAM does not protect against STIs.

A vasectomy blocks the tubes that carry sperm. It should be treated as permanent, even though reversal is sometimes attempted. It does not work immediately: another method is needed until follow-up semen testing confirms there are no sperm. It does not affect testosterone, erections or ejaculation.

Tubal surgery blocks or cuts the fallopian tubes so sperm and egg cannot meet. It requires surgery and should also be treated as permanent. It does not change hormones or the menstrual cycle. If pregnancy happens after tubal surgery, ectopic pregnancy is a concern and needs prompt assessment.

Both are highly effective but neither protects against STIs.

Pregnancy cannot occur if sperm does not enter or reach the vagina. Avoiding penis-in-vagina sex and keeping semen away from the vulva and vaginal opening is therefore an option. People define abstinence in different ways, so it helps to be specific with a partner about which activities you are avoiding.

Other sexual contact may still carry an STI risk through genital skin contact or exchange of sexual fluids. Condoms or other barriers may still be useful depending on the activity.

Seek advice promptly after penis-in-vagina sex without effective contraception, a broken or slipped condom, missed pills, a late injection, or another possible failure. Emergency contraception works best when arranged as soon as possible.

There are two types of emergency contraceptive pill in Australia, with different time windows of up to five days depending on the option. A copper IUD can be inserted within five days and can remain as ongoing contraception. Which option fits can depend on when sex occurred, body weight, medicines, breastfeeding, health history and plans for ongoing contraception. Ask a pharmacist, doctor or sexual-health service promptly even if you are unsure whether too much time has passed. They can also explain when to start or resume another method. Emergency contraception does not protect against STIs.

If your period is late after a possible failure, take a pregnancy test at the recommended time and seek advice if you are unsure when to test. Consider STI testing as well if there may have been exposure.

You do not need to choose before asking for advice. Useful questions include:

The answers can narrow the choices without assuming that hormonal or non-hormonal contraception is better for everyone.