How long does the pill take to work?

Dr Kathryn Basford

Medically reviewed by

Dr Kathryn Basford

Last reviewed: 04 Nov 2021

Depending on when you take the pill, it can get to work straight away so you’re protected from pregnancy. There are many different types of contraceptive pills to choose from when trying to prevent pregnancy, and you may be wondering how long the pill takes to work.

Let’s have a look at the difference between the combined pill and mini pill, and how long each takes to work.

Somebody about to take the contraceptive pill

How long does it take for the pill to work?

How long it takes for the pill to work depends on the type of pill you take. It could take between 1 to 7 days for the pill to take effect, depending on when you begin taking it, as long as you take it daily when you should, and do not miss any.

Combined pill

The combined pill is made of the hormones oestrogen and progesterone. This protects you from pregnancy by preventing the sperm from reaching the egg or by stopping ovulation (the release of the egg) that cycle.

You can start taking the combined pill at any point in your menstrual cycle. When you start taking the pill will determine when it begins to work.

If you start taking the combined pill between the first and fifth day of your period, you will be protected straight away.

But, if you start taking your combined pill after the fifth day of your period, you need to take it for 7 days in a row before you are protected. Use a condom during these 7 days so you do not get pregnant.

Mini pill

The mini pill is a progestogen only pill that prevents pregnancy by making sure that the sperm does not reach the egg.

When starting the mini pill, you should decide what time you want to take your pill, and continue taking it at the same time every day.

Similar to the combined pill, when the mini pill begins working is dependent on when you start taking it.

If you start taking the mini pill during the first 5 days of your period (days 1 to 5 of your menstrual cycle), it will start working right away. You will not need to use additional contraception, like condoms.

You will need to use a condom for the first 2 days of taking the pill if you begin taking the pill on any other day of your cycle, or if your normal period usually lasts less than 5 days.

How effective is the pill?

The contraceptive pill is 99% effective at preventing pregnancy if you take your pill without missing any. This means the pill is just as effective (99%) as the copper intrauterine device (IUD) and the contraceptive implant.

The pill is more effective than female diaphragms, which are only 88% effective, and female condoms that are only 95% effective.

However, the pill is not effective at preventing sexually transmitted infections (STIs), so it’s best to use a male condom when you have sex.

Am I still protected if I miss a pill?

If you miss a pill or start a new pack of pills late, you may be less protected from pregnancy.

The chance of getting pregnant when you miss a pill is dependent on:

  • how many pills you missed
  • where on the blister strip you missed the pill (either the beginning or end)
  • which contraceptive pill you are taking

You should read the patient information leaflet that comes with your pack of pills, or speak to a doctor for advice if you miss a pill.

With the combined pill, if you miss taking 1 pill anywhere in the pack or start a new pack a day late, you are still protected against getting pregnant. You should take the pill you last missed as soon as you realise, along with the pill you are due to take. Then carry on taking the rest of the pills as normal.

If you miss 2 or more pills anywhere in the pack, or are 2 or more days late starting a new pack, you may not be protected against pregnancy. This will depend where in the pack you are. Check with a doctor if you are not sure if you are still protected. You should use condoms for 7 days after you restart the pill.

You should take the pill you missed as soon as you realise, along with the pill you are due to take. Do not take the other pills you forgot to take. Carry on taking the rest of the pack as normal.

If you miss more than 7 pills, you are not protected from pregnancy and you need to speak to a doctor for advice as soon as you can.

Mini pill

If you forget to take the mini pill (progestogen only pill), you may not be protected depending on how long it has been since you forgot to take it. There are 2 types of mini pills, and they either need to be taken within the same 3 hour period or 12 hour period, each day.

If you are within the 3 or 12 hour time period, and you forgot to take your pill, take it as soon as you remember. You are protected against pregnancy and do not need emergency contraception if you had sex during this time.

Depending on your pill, if you are more than 3 or 12 hours late to take your pill, you are not protected. You should take the last pill you missed as soon as you remember, along with the pill you are due to take. Then, continue to take the rest of the pills as normal. You should use condoms for the next 2 days (48 hours) after you remember to take your missed pill.

If you’ve missed more than 2 pills, you need to speak to a doctor or pharmacist for advice.

Medically reviewed by:
Dr Kathryn Basford

Dr Kathryn Basford is a qualified GP who works as a GP in London, as well as with ZAVA. She graduated from the University of Manchester and completed her GP training through Whipps Cross Hospital in London.

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Article created: 04 Nov 2021

Last reviewed: 04 Nov 2021

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Contraceptive pills are a reliable way of reducing your risk of getting pregnant from sex. Asda Online Doctor by ZAVA offers most common brands of pill, so you can order your preferred brand by visiting our contraceptive pill service page.

(Reviews are for ZAVA UK)

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