Getting pregnant while on the pill is uncommon, but it does happen: with everyday use, about 7 in 100 people who rely on it become pregnant over a year, mostly after missed or late pills. This guide explains the early signs, why it happens, what to do after a late pill and when to test. If you think you are pregnant while on the pill, a pregnancy test and a doctor's advice are the next steps.
Key takeaways
- With everyday use, the pill prevents about 93 in 100 pregnancies over a year.
- Missed or late pills, vomiting and some medicines are the usual reasons it fails.
- Emergency contraception from a pharmacist can help after a missed pill and sex.
- A home test is reliable from the day your period is due, about three weeks after sex.
Early Signs You Might Be Pregnant
Early signs are often mild and easy to mistake for side effects of birth control. On the pill, the monthly bleed can be light or missing anyway, so a missed bleed alone does not prove you are pregnant while on the pill. Can you get pregnant on a birth control pill without any signs? Yes, so a test is the only sure answer.
| Sign | What it can feel like | Could the pill explain it? |
|---|---|---|
| A missed or very light bleed | No bleed in your break week, or much less than usual | Yes, the pill often makes bleeds lighter, and some people have none |
| Sore or swollen breasts | Tender, heavy or tingling breasts | Sometimes, in the first months of a new pill |
| Nausea | Feeling sick, with or without vomiting, at any time of day | Sometimes, mostly when a pill is newly started |
| Tiredness | Feeling more tired than usual for no clear reason | Rarely |
| Passing urine more often | Needing the toilet more, day and night | No |
| Light spotting | A few spots of blood around when a period would be due | Yes, spotting between bleeds is common on the pill |
If you have any of these signs after missed pills, do a pregnancy test, and repeat it a week later if it is negative but your bleed still has not come.
What Causes Getting Pregnant While on the Pill?
Most pregnancies on the pill happen because its hormones were not taken in steadily, which lets the ovaries release an egg. The most common reason is a missed or late pill, especially around the break, when starting a new pack late stretches the gap. Vomiting within three hours of a pill, or severe diarrhoea, can stop it being absorbed and counts as a missed pill. Some medicines, such as certain epilepsy and HIV treatments and the herbal remedy St John's wort, make the body clear the pill faster; most antibiotics do not.
Being pregnant while on the pill is also possible in the first days of a new pill, if it was started partway through a cycle and is not yet working. If any of these happened and you had sex, emergency contraception from a pharmacist, and condoms until the pill is working again, lower the chance of conceiving.
How Combined and Progestogen Only Types Compare
The pill comes in two types, and each has its own rules for a late dose. The combined pill contains an oestrogen and a progestogen and stops the ovaries releasing an egg each month. It counts as missed when it is more than 24 hours late. Take it as soon as you remember, even if that means two in one day, then use condoms for the next seven days. If it was in the last week of active pills, skip the inactive ones and start the next pack. If it was in the first week and you had sex in the five days before, ask a pharmacist about emergency contraception.
The progestogen only pill, with a progestogen (also called progestin) and no oestrogen, mainly thickens the mucus at the cervix. Traditional types are late after just three hours, and one newer type after 24 hours. Take a late one as soon as you remember, use condoms for the next two days with a traditional type or seven days with the newer one, and ask about emergency contraception if you had sex in that time. Both types are forms of birth control that prevent about 93 in 100 pregnancies with everyday use, so being pregnant while on the pill is equally uncommon with either.
Effects on a Baby of Early Hormone Use
Taking the pill in early pregnancy, before you knew, is not linked to birth defects or other harm to the baby. Large studies of people who kept taking birth control in the first weeks have found no rise in problems, so there is no need to worry on this account. Stop the pill once a test is positive.
Then start folic acid, if you are not taking it already, and see your doctor or a midwife to begin antenatal care. A pregnancy on the progestogen only pill has a slightly higher chance of being ectopic, growing outside the uterus, which is why a doctor may arrange an early ultrasound or blood tests. Your healthcare team can also review any other medicines you take. Contraception can be restarted after the birth, and a doctor can help you choose a method then.
Daily Habits That Keep Protection Working
Taking your pill at the same time every day is the habit that matters most. Link it to something you already do, such as brushing your teeth, and set a daily alarm. Keep a spare pack in your bag, and start each new pack on the right day, because a late start after the break is the most common time for birth control to fail.
When you are unwell with vomiting or diarrhoea, or start a new medicine, treat the pill as missed until it is working again and use condoms. Check any new medicine or herbal product with a pharmacist. If remembering a daily pill is hard, ask a doctor about longer acting contraception, such as an implant or IUD, which are fitted in person. Your healthcare team can review your pill each year, including your blood pressure, to keep the hormones right for you.
When a Test or Symptom Needs a Doctor
A positive pregnancy test, or a negative one with no bleed a week later, is the time to talk to a doctor. Home urine tests are reliable from the day your period would be due, about three weeks after the sex you are worried about; testing earlier can give a false negative. A doctor can arrange a blood test, which detects pregnancy earlier, and talk through your options.
If you think you might be pregnant on a birth control pill, keep taking it until a test confirms it, unless a doctor advises otherwise. Some symptoms need urgent care: pain low on one side of your belly, pain in the tip of your shoulder, heavy bleeding, or feeling faint or dizzy can mean an ectopic pregnancy. Go to an emergency department or call 000. Bleeding after sex, or pain during sex, also needs a check, as it can come from an infection.
Summary
Getting pregnant while on the pill is uncommon and usually follows a missed or late pill, vomiting or another medicine. This guide covered the early signs, the causes, the two pill types and their late pill rules, a baby's safety, daily habits and when to see a doctor. A Medio doctor can talk it through by phone and, where the doctor thinks it right, arrange a blood test or send an eScript for your pill.
Frequently asked questions
What happens if you get pregnant on birth control?
Usually nothing harmful happens to the pregnancy, and the first step is to confirm it, because the only way to know if you are pregnant is a test. If it is positive, stop the pill and see a doctor, who can talk through your options and start antenatal care if you continue. The chances of getting pregnant on the pill are low with careful use, so a positive result is worth checking promptly.
What can I do to get pregnant fast after family planning?
It is safe to get pregnant right after you stop using birth control, with no need to wait for a natural period. Start folic acid at least a month before, have sex every two to three days, and avoid smoking and alcohol. How long it can take to get pregnant varies, and most couples conceive within a year. See a doctor if it has not happened after 12 months, or after 6 months if you are 35 or older.
Can a doctor help with pregnant while on the pill?
Yes. In a telehealth consult by phone, a Medio doctor can talk through a missed pill, whether you need emergency contraception or a test, and what a result means. The doctor can arrange a blood test and, where the doctor thinks it right, prescribe your pill or a different one. Severe pain, heavy bleeding or feeling faint needs care in person straight away.
Is it possible to get pregnant while taking a progestogen only pill?
Yes. Like the combined pill, it is about 93 in 100 effective with everyday use, and more than 99 in 100 when taken on time every day. The factors that can lead to pregnancy on any pill are the same: late doses, vomiting and some medicines. Traditional types allow only a three hour window, so taking it at the same time each day, with a backup method for two days after a late dose, keeps the chance low.
Does the pill make you look younger?
No, there is no good evidence that the pill slows skin ageing or makes you look younger. Some combined pills can improve acne, and a doctor may suggest one for that reason, but results vary and are not a reason to pick a pill on their own. Birth control pills work mainly by stopping the release of an egg, and the birth control pill, often just called the pill, does nothing to skin age.
Why do I cry so easily on the pill?
The hormones in the pill can affect mood in some people, and crying easily, irritability or low mood are possible side effects. When you start taking the pill, these changes often settle within three months. Keep a note of how you feel and talk to a doctor, who may suggest a different pill or another method. If you feel very low or have thoughts of harming yourself, call Lifeline on 13 11 14, or 000 in an emergency.
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