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Information sheet: Contraceptive pill
PDF version: Contraceptive pill (ENG, PDF 131KB).
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The combined oral contraceptive pill, usually called “The Pill’, contains two hormones, oestrogen and progestogen. There are many different brands of the Pill available, and these differ in the type and amount of these two hormones.
How does it work?
In Australia, most Pill packets contain 28 pills – usually 21 active pills (hormone pills) and 7 inactive pills (“sugar pills”). Others have 24 hormone pills and 4 sugar pills. Some overseas brands come as 21-day packets where no pills are taken for seven days. With all types, you will have your period during the days without hormone pills.
The progestogen only pill, often called the “Mini Pill”, is a different type of contraception and is not discussed in this fact sheet.
How does the Pill work?
The Pill stops pregnancy by stopping the ovaries from releasing an egg each month. It also thickens the mucus/fluid at the cervix (opening to the uterus/womb) so that sperm cannot get through to meet an egg.
How effective is it?
The Pill is over 99% effective if correctly taken every day. It is important that you follow your doctor’s instructions carefully and take the tablets as described on the information leaflet in each pack.
Sometimes you may occasionally forget to take a pill, or illness and some medications may interfere with the Pill working, so in real life the Pill may only be 93% effective. All brands of the Pill have been shown to be equally effective in stopping pregnancy.
Will it work immediately?
If the Pill is started with a hormone tablet within the first 5 days of the menstrual cycle (where day one is the first day of your period), or within 5 days of an abortion or miscarriage, then it will be effective immediately. If the Pill is started at another time during your menstrual cycle, another form of contraception (such as condoms) should be used for the next seven days to avoid unplanned pregnancy. You should only start the Pill in this way after talking with your doctor to ensure you may not already be pregnant.
How long will it last?
The Pill will only provide contraception if you continue to take it every day. Missing a single pill can be enough to fall pregnant, and when you stop the Pill it is possible to become pregnant even before your next period. It does not take time for your fertility to return to normal.
There is also no need to “take a break” from the Pill. Most people can safely take the Pill for most of their lives, in consultation with a doctor.
What are the side effects?
Side effects to the Pill often settle with time and if not, changing to a lower dose or different type of Pill may often improve side effects.
Minor side effects can include:
- Breast tenderness
- Acne (many Pills will improve acne)
- Chloasma (pigmentation of the skin of the face)
- Lowered libido (sex drive) and mood change
- Spotting or “break through” bleeding
There is very little evidence that the Pill causes weight gain. Some people may put on weight, some may lose weight, but mostly there is little change.
Who should not take the Pill?
There are some circumstances and medical conditions that may be a significant risk to your health when taking the Pill. You should inform your doctor if you:
- Are over 35 years old and smoke
- Have high blood pressure
- Have had a deep vein thrombosis (blood clot)
- Have had heart disease or a stroke
- Suffer from migraines
- Have diabetes mellitus
- Have liver disease
- Have or have had breast cancer
- Have had unusual bleeding from the vagina
- Are taking any medications, especially for epilepsy
Your doctor will talk with you about the Pill and help you decide whether it is the best contraceptive method for you.
What if I am breastfeeding?
You should not take the Pill if you are breastfeeding in the first six weeks after birth. From 6 weeks to 6 months your doctor will discuss with you whether the Pill is appropriate for you. The Pill is considered safe in breastfeeding beyond 6 months.
Are there other benefits to being on the Pill?
The pill will usually help to improve acne, PMS and reduce heavy or painful periods. It can also be used to regulate the menstrual cycle if you have irregular periods. There is evidence that the Pill can reduce the risk of some cancers, such as of the ovary and endometrium (lining of the uterus) and can reduce ovarian cysts and manage symptoms of polycystic ovary syndrome
What if I forget a pill?
Taking the Pill correctly is essential for reliable contraception but if you forget a pill there are some simple rules to follow:
If the pill is less than 24 hours late:
- Take the late pill as soon as you remember and take your next pill at the usual time. This sometimes means taking two pills on the same day.
- You will not need to use any additional contraception.
If you are more than 24 hours late or have missed more than one pill:
- Take the most recent missed pill as soon as you remember and take the next pill at the usual time.
- Keep taking the pill as normal but use another form of contraception (such as condoms) until you have taken hormone pills for 7 days in a row.
- If you have less than 7 hormone pills left in your packet, do not take the “sugar pills” but go straight onto the hormone pills in a new packet. You may not get a period until the end of the new pack.
If you have unprotected sex and haven’t followed these rules you should seek emergency contraception (the “morning after” pill or a copper IUD insertion) as soon as possible.
Also, if you miss one of the first 7 hormone pills in a packet or start a new pack late and have had unprotected sex in the previous 5 days you should also consider taking emergency contraception as soon as possible.
(If you forget to take a “sugar pill” just continue taking pills daily. You will not need additional contraception.)
What else should I consider?
If you have diarrhoea or vomit within 2 hours after taking a pill continue taking the Pill as normal, but the rules for missed pills should be followed.
Antibiotics do not interfere with the Pill’s effectiveness and additional protection is no longer advised as necessary unless the antibiotics cause vomiting or diarrhoea.
The Pill offers no protection against STIs.
What if I have bleeding between periods?
The bleeding should stop after a day or two. Keep taking your pills and the problem will often stop after one or two cycles. However, if irregular bleeding keeps happening, speak with your doctor who may prescribe a different type of pill. Missing pills can increase the likelihood of “breakthrough” bleeding.
What if I miss my period?
Missing a period occurs in a small number of menstrual cycles, with some types of the Pill more likely than others. You should always check for possible pregnancy and speak with your doctor if you are at all worried.
Can I use the Pill to skip a period?
Periods can be skipped by going straight from the last active pill in the packet to the first active pill in the next packet. Sometimes your doctor may advise you to skip the sugar tablets and have continuous hormone tablets for an extended period of time. This can be useful to minimise periods if you suffer PMS or headaches with your periods or have endometriosis, or very heavy or painful periods. There is always the chance of getting break through bleeding when the Pill is taken in this way.
What about changing brands?
Your doctor may change you to a different brand of the Pill if you have ongoing side effects on one type of pill, or for medical reasons. Usually, you can stop taking the old Pill and start taking the new Pill from the first day of the next period.
Where can I get it?
You need a doctor’s prescription to get the Pill. You can get this from one of our centres, your local doctor or a family planning centre.
This page last edited: March 2023