Combined birth control pills contain two hormones, estrogen and progestin. 'Mini-pills', or progestin-only pills, only contain progestin.
The full name for the combined pill is Combined Oral Contraceptive Pill, or COCP. The full name for the 'mini-pill' is Progestin-Only Pill, or POP. But most people just call them both 'the pill'.
How well does it work?
(Read more about what 'failure rate' means in how well does it work?)
Typical use: 8 per cent
Perfect use: less than 1 per cent
The combined pill works very slightly better than the mini-pill.
- Very good at preventing pregnancy
- You can stop taking it to try and get pregnant whenever you like
- Makes periods lighter, reduces menstrual cramps
- No interruption during sex
- You don't need the man to cooperate
- You’ve got to take it every day – miss a day and you could get pregnant
- It doesn't protect against sexually transmitted diseases
- It can be expensive
- You need to see a health care provider and get a prescription
How do birth control pills work?
Combined birth control pills, with two hormones, stop you producing an egg. At the same time, they make the mucus around your cervix thicker so the sperm can’t get through.
Mini-pills, with only one hormone, work just because of this thickening of the mucus. But they also stop you producing an egg some of the time too, depending on the dose.
Who shouldn’t take birth control pills?
You shouldn't take any kind of birth control pills if:
- You’ve had breast cancer
- You’ve got blood clot problems that aren’t being successfully treated
- You think you’re pregnant. (But if you're on the pill and still got pregnant, it won't have harmed the baby – read more in pregnancy FAQs)
Who shouldn’t take combined birth control pills, rather than mini-pills?
You shouldn’t take combined birth control pills, if:
- You’ve had a long period of bed rest
- You have migraine headaches with auras, where it affects what you see
- You’ve inherited blood-clot disorders, have had blood clots, or inflamed veins
- You’ve had a heart attack, a stroke or, angina
- You’ve got serious heart valve problems
- You’ve got lupus
- You’ve had serious liver disease or liver cancer
- You’ve got very bad diabetes
- You’ve got uncontrolled high blood pressure
- You’re a smoker and are 35 or older
- You’re a smoker and have high blood pressure
This is why you need to see a health care provider and get a prescription before you go on the pill.
What should you do if you miss a pill?
Check the instructions for your brand of pill.
You need to take the pill at the same time every day. If you miss a pill, you should take the next one as soon as you can. You carry on taking the pill as normal. But at the same time, you need to use a backup birth control method, because otherwise, you could get pregnant.
- Combined birth control pill: if you take it more than 12 hours late, you need a back-up for seven days.
- Mini-pill: if you take it more than three hours late, you need a back-up for two days.
Back-ups might be a condom, female condom, diaphragm, or sponge. If you’ve had sex and think you might not have been properly protected, you can use emergency contraception.
What can stop the pill from working properly?
- If you’re very overweight, the pill might not work as well.
- Vomiting or diarrhoea can stop the pill from working properly - check the instructions for your brand of pill.
If you vomit within two or three hours of taking the pill your body might not have absorbed it properly. You should take another pill. But if you keep vomiting, you should use a backup birth control method for seven days after you get better.
- Do the same if you've had severe diarrhoea for more than 24 hours.
- Certain medicines might stop the pill from working as well. They include medication for yeast infections, HIV and epilepsy, and the herbal remedy St John’s wort.
- You need to check with a healthcare professional if you’re taking medicines along with the pill.
How safe are birth control pills?
After a few months, most women find the pill doesn't give them any side effects.
Some women find they don't feel like having sex as much. If this carries on for more than three months, talk to your healthcare provider about changing your prescription.
When you stop taking the pill it can take one or two months before your period cycle returns to normal. If you had irregular periods before taking the pill, they might be even more irregular when you stop. Talk to your healthcare provider if you're worried about this.
During the first two to three months, you may have:
- Tender breasts
- Bleeding between periods (more likely with the progestin-only or 'mini-pill')
If you take your pill every evening or at bedtime, you're less likely to experience nausea and vomiting.
If you’re still experiencing nausea after three months, talk with your healthcare provider about changing your prescription.
Remember if you stop taking the pill because it's making you feel sick, you will be at risk of getting pregnant. You'll need to use another birth control method if you have intercourse.
Combined birth control pills very slightly increase the risk of certain serious health problems including heart attacks, strokes or blood clots. The risk gets higher if you're over 35 or you smoke.
Progestin-only pills have fewer serious side effects than combination birth control pills. Ask your health care provider about switching if you’re getting side-effects on combined pills.
Immediately contact your nearest health care provider, if you:
- Get a new lump in your breast
- See a bright flashing zigzag light (an aura) before getting a very bad headache
- Have a sudden very bad headache
- Have different or more headaches than usual
- Get sore, achy legs
- Notice your skin or eyes are turning yellow
- Have no period after having a period every month
How do I get birth control pills?
First go to your nearest health care provider for a prescription. They’ll first ask you about your medical history and check your blood pressure. After ruling out any serious conditions, they’ll give you a prescription.
The cost of the pills depends on where you live.
Do birth control pills have any health benefits?
Both combined and progestin-only birth control pills can:
- Make your periods more regular and lighter
- Reduce your menstrual cramps
- Give some protection against pelvic inflammatory disease, which if left untreated it can make you infertile
The combined birth control pill can also:
- Reduce your acne
- Makes you less likely to have an ectopic pregnancy, if you get pregnant
- Makes you less likely to get cancer of the womb or cysts on your ovaries
- Makes you less likely to get iron deficiency anaemia