Can you get pregnant while on birth control pills?

Birth control pills are considered effective, but not entirely foolproof. They’re about 99% effective when you take them correctly.

But that’s if you take them perfectly, meaning at the same time each and every day. If you don’t, your odds of becoming pregnant go up to 9%.

Five reasons for pill failure

Although the birth control pill is generally very effective, some situations can reduce its effectiveness and may sometimes result in unintended pregnancies. These include:

Missing a day

Manufacturers intend for people to take the pill daily for it to be most effective. If a person misses a day, their hormone levels may not remain at consistent enough levels to prevent pregnancy.

If a person finds it difficult to take the pill on a daily basis, other birth control methods may better suit their needs. A doctor or gynecologist can advise on the range of alternative contraceptives.

Vomiting

Sometimes a person may be ill when they take the pill. When a person vomits, the pill can come back up, or they may not fully absorb it into their body.

Anyone who experiences vomiting shortly after taking the pill should take another pill as soon as possible and then take their next pill as usual.

Not taking the pills at the same time each day.

In addition to taking birth control pills daily, a person should also take the pills at around the same time each day. This can maintain their hormone levels more consistently.

A person should always take the minipill within the same 3-hour time window every day. Someone who misses their window should use a backup birth control method for the next 2 days or avoid having sex.

Many people set a daily alarm reminding them to take their pill at the correct time each day.

Not starting a new pack right away

It is essential to start a new pack of pills the day after finishing the previous one. However, sometimes a person may not have their new package yet. Missing a few days between packs can make the pill less effective at preventing pregnancy.

According to the CDC, anyone who misses two or more pills in a row should use a backup contraceptive method or avoid sexual intercourse until they have taken the birth control pill for 7 consecutive days.

RELATED: Common pregnancy signs before missed period 

Medications that interfere with the pill

Some medications can make the pill less effective. Medications include certain antibiotics, such as rifampicin, and anti-fungal drugs, such as griseofulvin.

A person should use backup contraception while taking these medications and for 48 hours after finishing the course.

Other more long-term medications and supplements may also affect how well birth control pills work. These can include:

  • epilepsy drugs, such as phenobarbital, phenytoin, and carbamazepine
  • anti-viral medications used to treat HIV
  • St. John’s Wort, which is a herbal remedy

Tips for preventing pill failure

Birth control pills are very effective if a person takes them correctly and does not miss any pill days. The following tips can help prevent unintended pregnancies while taking the pill:

  • reading the packaging and following the instructions carefully
  • taking the pill at the same time every day
  • using an app that tracks periods and provides pills reminders, such as one of the apps from our review article
  • always getting a new pill pack at least 1 week before the last pill pack is due to run out
  • always taking missed pills as soon as possible
  • using a backup method of contraception, such as a condom, if a person misses taking two or more pills in a row

Outlook

If a person is concerned about not being able to take their pills consistently, they should speak to their doctor or gynecologist about other birth control methods. There are several options available that do not require taking a pill daily, such as an intrauterine device, or IUD.

While birth control pills are generally very effective, they can sometimes fail to prevent pregnancies if a person does not use them correctly and consistently.

Anyone who is concerned about the effectiveness or convenience of their method of contraception should speak to a doctor.

If a person misses taking more than one pill, they should use a backup contraceptive method for at least 7 consecutive days of retaking the pill.

Categories: Reproductive health

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