How Likely Is It to Get Pregnant While on Birth Control Pills?

How likely is it to get pregnant while on the pill?

Birth Control Pills
Birth control pills are over 99% effective when taken correctly and regularly as prescribed.

None of the methods used for birth control are 100% effective. There is a possibility, although rare, of getting pregnant while on birth control pills. Birth control pills are over 99% effective when taken correctly and regularly as prescribed.

What causes the failure of birth control pills?

Several factors that may be directly or indirectly related to the failure of birth control pills, causing pregnancy, are:

  • Taking the pills irregularly or at a different time each day
  • Vomiting and diarrhea for more than 48 hours
  • Some antibiotics, antifungals and anti-seizure medicines
  • Some HIV medications
  • The herb St. John’s Wort
  • The pill may not work for people who are overweight

How would you know if you were pregnant while taking the pill?

If a woman on birth control pills gets pregnant, she may notice the following symptoms:

If you experience any of these symptoms, get a pregnancy test done at home or in a clinic/lab.

Are birth control pills more effective than condoms?

Yes, the typical effectiveness of a pill ranges from 91% to 99%. The failure rate for the pill is 1% to 9%, whereas for male condoms, it is 13% and for female condoms it is 21%.

How long does it take for birth control pills to work?

The time it takes birth control pills to work depends on when you start taking them and what type of pills you use. You may begin taking the birth control pill any day of the month. It is; however, advisable to use a backup birth control method, such as condoms, for about a week once you start taking the pills.

Combination oral contraceptive pills (COCs)

  • When started within five days after the first day of your period, the combined pill will protect you from pregnancy right away.
  • If you get your periods on a Monday morning and you start taking the combined pills any time before Saturday morning, you will be instantly protected from a possible pregnancy.
  • If the pills are started at any other time, it is best to use an additional method of birth control, like a condom, for the first week after you start taking the combined pills.

Progestin-only pills (Mini pills)

  • Progestin-only pills, POPs or mini pills can be started any day of the month. They will protect you from pregnancy after 48 hours (two days) of taking the first pill.
  • In this case, you must use another method of birth control (like a condom) to prevent pregnancy during the first two days.

You must always discuss with your nurse or doctor about which birth control pill option would be best for you.


Which of the following are methods for contraception? See Answer
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