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Can I get pregnant while on the pill?

Yes, you can, the pill isn't 100% safe...

Posted: 6 November 2010
by Kimberley Smith

Woman looking worried holding a packet of contraceptive pills
Just because you're on the pill doesn't mean you won't be pregnant

The Pill: fail-safe contraception?

This is a very frequently asked question, and the answer is yes, it certainly is possible to become pregnant when you’re on the pill. A standard birth control pill is effective about 99.5% of the time if it is used absolutely correctly, so if you use the pill to the letter of the instructions you have a 0.5% chance of becoming pregnant over the course of one year. You could get pregnant even if you do everything right. And if you aren’t scrupulous about following instructions, the pill is far less effective. Studies vary but some show a user failure rate of over 5%, meaning that in the real world as many as 5% of the women on the pill will become pregnant over the course of one year.

What increases the failure rate?

One of the most common failings in taking the pill properly is forgetting to take a pill entirely, particularly in the first few days of the cycle. It’s also possible to take a pill and for the pill never to enter your system because of a stomach upset with vomiting or diarrhoea. If either of these things happen to you you should check the manufacturer’s instructions about doubling up with an alternative contraception for a period of time.

Some other medications, such as antibiotics and migraine medicines, can affect the effectiveness of the pill, so you need to be sure your doctor is aware you’re on the pill before prescribing other medicines for you and that you take other contraceptive measures when necessary.<p>
If you’re using a back-up method of contraception because the effectiveness of the pill has been compromised in some way, then remember during that time your contraception is only as effective as the back-up method you are using.

How will I know if I’m pregnant?

The most usual way to realise that you’re pregnant when you’re on the pill is when your period doesn’t arrive as usual. You may also experience some physical early signs and symptoms of pregnancy, even in early weeks, such as tingling, sore or heavy breasts, and mild cramping. If you think you could be pregnant then take a home test as soon as you miss your period or arrange a test with your doctor.

There’s no hard evidence that using the pill when pregnant will harm your baby, but it could, so it makes sense to stop taking the pill as soon as you realise that you’re pregnant and see our advice for an unexpected pregnancy. Find out more about contraception after birth and long term contraception for parents.


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Discuss this story

All the paper work will tell you that all birth control methods are 99.9% effective if taken correctly. But what about that .1%? Well I am in that tiny group. I used the pill as my main cours of contraseptive since I was 16. I am now 22 with a 13 month old daughter. I am living proof that you CAN get pregnant while using the pill. I know what your thinking... "she must have not taken it correctly or forgotten a pill" or "she must have been sick or on antibiotics or something." Nope. I got pregnant the first time about a year out of High School. However, it was spontaniously aborted by my body. I like to think that it became a miscarriage BECAUSE of the birth control pill.
After that, my now husband and I were VERY careful in making sure we did everything right. We used condoms every time, even though I was still taking the pill, convinced last time was a fluke. Well about 6 months after I misscarried, my husband asked me to marry him. In the middle of "celebrating" our engagement, the condom broke. Low and behold, I have a beautiful 13 month old daughter, perfect to a T.
I am in the .1% of women who the pill had failed to protect. I'm not mad... Its just inneffective in me, I guess.

Posted: 20/02/2007 at 15:40

heather your not alone.

i concieved on the pill and i never ever forgot one or took it late. it does happen. little harry wasnt going to let anything like a contraceptive pill stop him lol, hes four months now and hes just perfect.

Posted: 20/02/2007 at 16:04

Hi heather, i too fell pregnant on the pill with Lucie who is now nearly five! I'm now pregnant with my 3rd who i fell pregnant with using condoms! what are the chances of being in the 0.1% twice!!!!!

I'm going to try the coil next as i'm incompatable with the injection and implant, but have also considered being sterilised but my doctor says at 24 i'm too young. Seems i'm not allowed to decide when i've had enough children!

Louise xx

Posted: 21/02/2007 at 09:49

i was also on the pill and I am now 18 weeks pregnant, bit of a shock at first but i cant wait.

Just goes to show ladies that these babies really are meant to be, they were determined to be in your life for a reason.

kel xx

Posted: 22/02/2007 at 09:40

i too fell pregnant whilst on the pill. It really upset me because i know i took it properly, but the first thing my parents did was accuse me of not using contraceptives. I told them i was taking my pill properly, hadnt been sick or had diarrhea or anything. They still dont believe me to this day, and my son is about to turn 4!!!

Posted: 22/02/2007 at 17:52

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