When you miss pill pills, your body is not protected against pregnancy. The amount of time it takes for the pill to protect you varies by type and formulation.
The pill is 99 percent effective when taken correctly. But about one in ten women get pregnant while taking it. This can be because of a range of things like vomiting or diarrhoea, and taking medicines that interfere with the pill’s absorption, such as rifampicin (used to treat tuberculosis).
How long is the protection window?
Generally speaking, birth control pills are most effective when taken around the same time every day. But this isn’t a hard and fast rule. It’s fine to take your pill an hour earlier or later than usual, especially during daylight saving time in the spring and fall when our clocks move forward or back one hour.
The protection window differs between pill types, as well as how many pills a person has missed in a row. But it’s usually less than 24 hours for combo pills and less than 3 hours for progestin-only ones (aka minipills). If you miss a pill within this window, the next pill should provide full protection, so you don’t have to worry about pregnancy.
However, if you’re more than 24 hours late or more than a day late, it’s a good idea to use a backup method of birth control for the rest of that pack. This gives you a chance to get back on track for the next few days while hormone levels return to their protective level.
Similarly, if you start your pill mid-cycle, it can take some time for the hormones to stabilize. If you’re worried, ask your health care provider for advice. They can help you decide on the right pill type and dosage for your situation and menstrual cycle, and recommend back-up contraception if needed.
What if I miss a pill?
A few hours here and there or even missing one pill isn’t a big deal for the majority of women using combination birth control pills. However, where in the pack you are when you miss a pill can make a difference. If you miss a pill early in your cycle, it can prevent ovulation from happening and thicken cervical fluid so that it is harder for sperm to penetrate the uterus and fertilize an egg (3-5).
If you’re well into your pack or starting a new pack when you miss a pill, you may need to use backup methods like condoms for two days to protect against pregnancy. This is because you’ve come off a seven day break from the hormones, and there may not be enough left in your system to protect against pregnancy.
If you’re still within the five hour safe window — such as when you switch your pill time from 8am to 7pm to accommodate your sleep schedule — it shouldn’t change how effective the pill is. This means your risk of pregnancy is still very low and you shouldn’t need to use extra contraception for a few days. However, it is still important to take your pill at the time you usually do. If you don’t, it could cause an increase in the chance of getting pregnant due to unprotected sex and not taking the pill at its usual time (6-9).
What if I’m too late?
If you miss a pill, it’s important to remember that your birth control is only effective if you take all of the pills in the pack, on time. This includes the inactive or placebo pills, which may be a different color than the active ones. If you are more than three hours late, you could experience break-through bleeding and the pill’s effectiveness will decrease.
If the pill you took wasn’t in the protection window (it depends on where you are in the pack and what type of pill you’re taking) or if it was a progestin-only pill, you will need to use back-up contraception for two days. If you’re not sure how long your protection window is, check the packaging or talk to your health care provider.
Your health care provider will help you figure out which combination birth control pill is right for you. They will consider your lifestyle, any medical conditions or other medications you are on and your personal preferences to find the best plan for you. This will include a physical exam, blood pressure measurements and an interview. It will also be a chance for you to ask your questions about the pill. The most common types of combination birth control pills are 21 active pills and seven inactive pills, but some packs have fewer or more inactive pills.
What if I’m too early?
If you’re using a combination birth control pill that contains both estrogen and progesterone, it can still work well even if you’re off by up to five hours from your usual time each day. However, it’s better to be closer than that.
For the progestin-only pill (sometimes called the minipill), you’ll want to be even more exact about your timing. If you’re off by just a few hours, the hormones won’t have had time to kick in and will be less effective.
With both types of pills, missing just one pill and having unprotected sex increases pregnancy risk. It’s also important to note where in the pack you’re at when you miss a pill. If it’s at the end of your pack or in the first week of a new one, your chance of pregnancy is higher than if you skip a pill at any other point in the pack.
Most combination pills are a 28-day pack that provides protection against pregnancy for 21 days followed by a week of taking no or pills that don’t contain hormones (a period). Some brands offer a continuous-dosing option, which may help to reduce the number of monthly periods. Talk to your health care provider to decide if a combo or progestin-only pill is right for you. They can also advise on the best back-up methods for your situation.