Can You Get Pregnant When on the Pill
If you have typed "can u get pregnant when on the pill" into your phone late at night, you are in good company. It is one of the questions I am asked most often in clinic, and it usually comes with a knot in the stomach: a pill was late, someone was sick, a new medicine was started, or a period has not turned up.
The short answer is yes, you can get pregnant on the pill. But it is uncommon when the pill is taken exactly as directed, and in most cases there is a clear, fixable reason when it does happen.
I'm Dr Lisa Chavda. I have been a GP for 16 years, I hold the Diploma of the Faculty of Sexual and Reproductive Healthcare, and I set up two NHS family planning clinics in my London surgeries. Today I see patients privately in Harley Street and Enfield. In this guide I'll explain the real chances, what raises the risk, what pregnancy symptoms on the pill can look like, and exactly what I would do next.
Can you get pregnant on the contraceptive pill? The short answer
Yes. No contraceptive method except not having sex is 100% reliable, and the contraceptive pill is no exception. What matters is how it is used.
When the pill is taken at the same time every day with no missed doses, it works extremely well. The trouble is that real life gets in the way. Alarms fail, packs run out, stomach bugs happen, and a new prescription from another doctor may interfere. When I see someone who has become pregnant on the pill, there is nearly always a reason like this behind it, rather than the pill "just not working".
What are the chances of getting pregnant on the pill
There are two numbers worth knowing, and the gap between them is the whole story.
How the pill is used | Chance of pregnancy in one year |
Perfect use (every pill, on time, no interacting medicines) | Fewer than 1 in 100 (more than 99% effective) |
Typical use (real life: late or missed pills, sickness, interactions) | About 9 in 100 (around 91% effective) |
These figures come from the NHS guidance on how well contraception works. Typical use includes everyone who sometimes forgets a pill, takes it late, or is ill, which is why it is lower.
Combined pill or mini pill? The chances are the same for both in typical use. The mini pill (progestogen-only pill) has tighter timing rules, which I explain below, so it is less forgiving if you take it late.
Can you get pregnant if you take the pill every day
If you take it every day, on time, and nothing interferes with it, your risk is under 1 in 100 over a year. That is low but not zero. Rarely, ovulation can break through even with perfect use, and sometimes absorption or an unrecognised medicine interaction is the cause. This is why I always tell people that if they have had a missed period and are worried, a test is worth doing even if they feel sure they have done everything right.
How does the "pregnancy pill" work
People use the term "pregnancy pill" for a few different things, so let me clarify. Most often they mean the contraceptive pill, which prevents pregnancy. Sometimes they mean the emergency pill (the morning after pill). Neither ends an existing pregnancy.
The contraceptive pill
The combined pill contains two hormones, oestrogen and progestogen. It works in three ways:
It stops ovulation, so no egg is released.
It thickens the mucus at the cervix, making it hard for sperm to get through.
It thins the lining of the womb, making it less welcoming for an egg.
The mini pill contains only progestogen. Older mini pills work mainly by thickening cervical mucus, while the desogestrel mini pill (such as Cerazette or Cerelle) also stops ovulation in most people.
This is why a missed pill matters. If hormone levels dip, your body can start to release an egg again.
The emergency pill
The emergency pill is different. It is taken after unprotected sex or a contraceptive failure and works mainly by delaying ovulation. It will not work if ovulation has already happened, and it is not meant to be used as regular contraception. I explain the timing in more detail in my guide on how to prevent pregnancy after unprotected sex.
If you are searching because you want to end a pregnancy that has already started, neither pill will do that. Please speak to your GP or a sexual health service, and I'll point you to the right places later in this article.
Pregnancy pill effectiveness: contraceptive pill vs emergency pill
The contraceptive pill
Effectiveness depends almost entirely on how consistently it is taken. More than 99% with perfect use, about 91% with typical use. Taking it continuously with no pill-free break, which some people choose for lighter or fewer bleeds, is just as effective if done correctly.
The emergency pill
Emergency contraception is time-sensitive: the sooner you take it, the better it works. There are two types:
Levonorgestrel (for example Levonelle): taken within 3 days (72 hours) of unprotected sex.
Ulipristal (ellaOne): taken within 5 days (120 hours).
The copper coil is the most effective form of emergency contraception, and it can be fitted up to 5 days after unprotected sex. It can then stay in place as ongoing, hormone-free contraception.
Weight matters with emergency pills, which many people do not realise. Current guidance says levonorgestrel appears less effective above a BMI of about 26 or a weight of about 70 kg, and ulipristal may be less effective above a BMI of about 30 or about 85 kg. If this applies to you, the copper coil is usually the better choice, so please ask.
For the everyday contraceptive pill, most evidence suggests weight does not change how well it works.
How long does the contraceptive pill take to work
This is another very common question: with contraceptive pills, how long does it take to work? It depends on the type and when you start.
Pill | When you are protected |
Combined pill | Straight away if you start on days 1 to 5 of your period. At any other time, you need to take 7 pills in a row, using condoms or avoiding sex in the meantime. |
Mini pill (traditional or desogestrel) | Straight away if you start on days 1 to 5 of your period. At any other time, 2 days of pills plus condoms. |
Drospirenone mini pill (Slynd) | Protected straight away only if started on day 1. Otherwise 7 days. |
Brands with different rules (for example Qlaira) | Check the leaflet, as these differ. |
A few more situations to know about:
If you have taken ulipristal emergency contraception, you need to wait 5 days before starting a hormonal pill, using condoms during that time.
If you are switching from another method, or have just had a baby or a miscarriage, the timing can differ, so please check with your doctor.
If you are unsure, the safest rule is to use condoms for the first 7 days of any new pill.
How to take pregnancy pills correctly
If you are asking how to take pregnancy pills (the contraceptive pill), here is how I explain it to patients.
The combined pill, 21-day pack: take one pill at the same time every day for 21 days, then stop for 7 days. You will usually have a withdrawal bleed in that break. Start the next pack on day 8 even if you are still bleeding.
The combined pill, 28-day pack (with 7 inactive pills): take one every day with no break between packs. Take the inactive pills on days 22 to 28, then go straight to the next pack.
Continuous use: some combined pills can be taken without a break for fewer bleeds. This is safe and just as effective if done correctly, but it is worth discussing with your doctor first.
The mini pill: take one every day at the same time, with no break at all.
What can cause you to get pregnant on the pill?
In my experience these are the reasons that matter most.
Missed or late pills
This is the most common cause. The rules depend on your pill:
Combined pill: a pill counts as missed if it is more than 24 hours late.
Traditional mini pill: it must be taken within 3 hours of your usual time.
Desogestrel mini pill (Cerazette, Cerelle): you have a 12-hour window.
Anything beyond this window counts as a missed pill.
Vomiting and diarrhoea
If you vomit within 2 hours of taking a combined pill, the hormones may not have been absorbed, so take another straight away. For the mini pill, the time window varies by brand, so check your leaflet. Severe or prolonged diarrhoea can also stop the pill working, so treat each affected day like a missed pill and use condoms as advised.
Medicines that interfere
A few medicines can make the pill less reliable by speeding up how fast your liver breaks it down:
the antibiotics rifampicin and rifabutin
the antifungal griseofulvin
some epilepsy medicines (such as carbamazepine, phenytoin and topiramate)
some HIV medicines
the herbal remedy St John's wort
Most common antibiotics, such as those for chest or urine infections, do not interfere with the pill. Even so, always tell your doctor or pharmacist you take it before starting anything new.
Starting a pack late, or starting the pill late
If you start a new pack late, you have effectively lengthened your pill-free break, which gives the ovaries time to restart. I explain this under "The riskiest time to miss a pill" below.
Gut conditions
Conditions that affect absorption, such as severe diarrhoeal illness or some bowel diseases, can in theory reduce how much of the pill you absorb. If you have one, mention it when choosing contraception.
Poor storage
Heat, light and damp can damage the pill. Keep it in a cool, dry place, such as a bedroom drawer, not in a bathroom or a hot car.
The riskiest time to miss a pill
The timing of a missed pill matters more than most people realise. The most dangerous time is just before or just after your pill-free break, because a missed pill there makes the break longer, and your ovaries can wake up and release an egg. If you have missed pills in the first week of a pack, or at the end of the previous pack, and then had unprotected sex, emergency contraception should be considered.
Can you get pregnant in the pill-free break
No, as long as you took the previous 7 pills correctly and you start your next pack on time. The break itself does not remove your protection. The risk comes from mistakes around it, as above.
What to do if you have missed a pill
This is a simplified guide for the combined pill. Always check your own leaflet.
Situation | What to do | Extra protection |
1 pill missed (more than 24 and up to 48 hours late) | Take it now, even if that means two in a day, then carry on as normal | Not needed |
2 or more pills missed (more than 48 hours late) | Take the most recent missed pill now, leave any earlier ones, and carry on | Condoms or no sex until you have taken 7 pills in a row |
Missed in week 1, with unprotected sex in the last 7 days | As above | Consider emergency contraception |
Missed in week 2 | As above | Emergency contraception is usually not needed if the 7 pills before were taken correctly |
Missed in week 3 | As above, then finish the pack and start the next one without a break | Condoms until 7 pills in a row |
Mini pill: if you are outside your window (3 hours for a traditional mini pill, 12 hours for a desogestrel pill), take it now, carry on, and use condoms for 2 days. Consider emergency contraception if you have had unprotected sex since.
Pregnant symptoms on the pill
Pregnant symptoms on the pill are the same as without it, which is exactly what makes them confusing. The early signs include:
feeling or being sick
sore or tender breasts
feeling unusually tired
needing to pass urine more often
going off certain foods or smells, or new cravings
constipation
a missed period, or unusually light bleeding
Many of these are also common pill side effects, especially in the first few months, so symptoms alone can't tell you.
Bleeding can be misleading. On the pill you have a withdrawal bleed, not a true period. Some people still have light bleeding or spotting in early pregnancy, and it can look like a period. A bleed does not rule out pregnancy, particularly if you have missed pills.
The pill does not affect pregnancy tests. Home tests detect the hormone hCG, which the pill does not contain. So a test is reliable.
When to test: take a test about 3 weeks after unprotected sex, or from the first day of a missed or unusually light bleed. If it is negative but you are still worried, repeat it a few days later.
One safety point: if you have one-sided lower tummy pain, pain at the tip of your shoulder, vaginal bleeding with dizziness or fainting, seek urgent medical help the same day. These can be signs of an ectopic pregnancy. The pill does not increase this risk, but any pregnancy that happens on contraception should be checked early to make sure it is in the right place.
What to do if you think you are pregnant on the pill
Take a pregnancy test as soon as you can.
If it is negative but you are worried, keep taking your pills and repeat the test in a few days. Stopping the pill could increase your chance of conceiving.
If it is positive, contact your GP or a sexual health clinic. They will usually advise you to stop the pill, and they can talk you through your options in a non-judgmental way.
Will the pill harm a pregnancy? This is a very common worry. A large Danish study published in the BMJ found no link between using the pill and birth defects, and there is no good evidence that taking it in early pregnancy causes harm. Research is limited, so I always advise stopping once pregnancy is confirmed.
If you are not sure what you want to do, that is completely normal. Your GP, the NHS and sexual health services can talk you through all of your options without pressure.
How to stop the pill letting you down
Take it at the same time every day, linked to a daily habit.
Set two alarms, or use an app.
Use condoms if you miss a pill, are late, or are ill.
Check every new medicine with a pharmacist or doctor.
Store the pack somewhere cool and dry.
Order your next pack before you run out.
Read the leaflet for your own brand, because rules vary.
If the pill keeps letting you down: more reliable options
If you are reading this because the pill has caused you worry more than once, it is worth asking whether a method you do not have to remember would suit you better.
A large US study published in the New England Journal of Medicine found that people using the pill, patch or ring had around 20 times the risk of contraceptive failure compared with people using long-acting reversible contraception (LARC).
Method | Chance of pregnancy in a year |
Pill, typical use | About 9 in 100 |
Contraceptive implant | Fewer than 1 in 100 (more than 99% effective) |
Coils (copper and hormonal) | Fewer than 1 in 100 (more than 99% effective) |
The implant, the copper coil and the hormonal coil all work without you having to remember anything each day. You can read more about how the coil is fitted and who can use the contraceptive implant. If you would like to compare all your choices, my guide to 15 contraceptive methods is a good place to start.
I fit and remove implants and coils privately at my clinics in Harley Street and Enfield. You can book an implant fitting, read about copper coil fitting, or call me to talk it through first.
Frequently asked questions
Q1. Can u get pregnant when on the pill?
Yes, though it is uncommon. With perfect use fewer than 1 in 100 people become pregnant in a year. With typical use it is about 9 in 100, mainly because of missed pills, sickness, diarrhoea and some medicines.
Q2. What are the chances of getting pregnant on the pill?
Fewer than 1 in 100 per year with perfect use and about 9 in 100 with typical use. The chances are the same for the combined and mini pill.
Q3. Can you get pregnant on the contraceptive pill if you take it every day?
It is very unlikely, but not impossible. Rarely, ovulation can break through even with perfect use, or a medicine or illness can affect absorption.
Q4. Can you get pregnant if you miss one pill?
One missed combined pill (more than 24 hours late, up to 48) usually does not need extra protection if you take it as soon as you remember. Two or more missed pills do, so follow the table above.
Q5. Do antibiotics make the pill less effective?
Most do not. The exceptions are rifampicin and rifabutin, plus the antifungal griseofulvin. Always check with your pharmacist.
Q6. Can you get pregnant in the pill break?
Not if you took your last 7 pills correctly and start the next pack on time.
Q7. Can you get pregnant on the pill while ovulating?
The pill is designed to stop ovulation. If you miss pills, especially around the pill-free break, your ovaries can release an egg, and sex around then can lead to pregnancy.
Q8. Can you get a period if you are pregnant on the pill?
You will not have a true period, but you can have light bleeding or spotting that looks like one. If you are in any doubt, do a test.
Q9. Does the pill increase the risk of ectopic pregnancy?
No, the pill lowers your overall chance of pregnancy, including ectopic. But if you do become pregnant on contraception, it is sensible to have an early check to confirm the pregnancy is in the womb.
Q10. Can you get pregnant on the contraceptive injection?
It is possible but very uncommon when your injections are on time, every 12 to 13 weeks depending on the type. Late injections are the main cause.
Q11. Can I get emergency contraception if I missed pills?
Yes. Emergency contraception may be needed depending on which pills you missed and when you had sex. The copper coil can be fitted up to 5 days afterwards, and emergency pills work up to 3 or 5 days depending on the type. See my morning after pill page.
About the author
Dr Lisa Briscoe Chavda BSc MBBS MRCP DFSRH MRCGP is a GP and contraception specialist with 16 years' experience. She is registered with the GMC (6049134) and the CQC, and established two NHS family planning clinics within her London GP surgeries. She sees patients privately at 10 Harley Street, Marylebone, and in Enfield.
Medically reviewed by Dr Lisa Chavda. Last reviewed: [add date].
This article is for information and does not replace personal medical advice. If you think you are pregnant, are worried about a missed pill, or need emergency contraception, please speak to a doctor or pharmacist promptly.
Sources
NHS: Combined pill
NHS inform: Combined pill
College of Sexual and Reproductive Health (formerly FSRH): Combined Hormonal Contraception guideline and Progestogen-Only Pills guideline (amended April 2026)
FSRH: Overweight, Obesity and Contraception guideline (April 2019)
Peipert JF et al. Effectiveness of long-acting reversible contraception. New England Journal of Medicine
Maternal use of oral contraceptives and risk of birth defects in Denmark. BMJ
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