How Soon Do Birth Control Pills Become Effective?

When women use birth control pills, they have many more choices and a lot more freedom than other methods of birth control. Most women who start using birth control pills want to enjoy these advantages as soon as possible, but how soon do birth control pills become effective?

How Soon Do Birth Control Pills Become Effective?

If you are among the millions of women in the US who are choosing to start to use birth control pills this year, you need to know ‘the pill’ is often not instantly effective. It can take a long time before your birth control pills are able to protect you against unwanted pregnancy.

But precisely how much time depends on several factors. Some of these factors include the specific type of birth control pills you are taking and how far along you are in your menstrual cycle when you take the first pill. It is critical to understand how these factors can affect you.

Check also our earlier blog post on when should you start the pill.

How the Types of Pills and Your Menstrual Cycle Affects the Effectiveness of Birth Control Pills

There are two main types of birth control pills: combination pills and progestin-only pills. There are benefits and drawbacks for each of these two varieties. Your doctor tends to make the final decision about which type of pill is best for you. If you prefer one type of pill or have concerns, talk to your physician.

A combination pill is the most common type of birth control. The pill contains both progestin and estrogen hormones. Women who use this kind of birth control pill may need to wait up to 7 days before the pill can protect them against unwanted pregnancy.

During this waiting period, it is still possible for these women to engage in intercourse, but they should continue to use an alternative method of birth control such as a condom and spermicidal gel.

For a woman who thinks that 7 days is too long of a time to wait, there is good news.

There is a way for women to eliminate the waiting period completely. Women who take their first combination pill on the initial day of their periods are free to have sex with a far less chance of becoming pregnant from day one.

A progestin-only pill, most commonly known as the ‘minipill’ or POP, only contains the hormone progestin. One advantage of using the minipill is that it takes only 48 hours for progestin-only pills to become effective against pregnancy.

For the first two days after beginning the minipill, couples need to use an alternative method of birth control. It is important to note that with the minipill, women must take the pill at the same time each day to stay protected.

Missing a pill by as little as three hours means you have to take precautions.

Missing a pill by as little as three hours can mean having to use a backup method for 48 hours. Forgetting to take a pill for an entire day will mean 2 weeks of using an alternative birth control method.

This is only a guideline for how soon do birth control pills become effective and everyone is different. Listen to your doctor and always ask questions when you have any concerns about your health.

(A clinical pilot – DOI: 10.15761/COGRM.1000217, was conducted by a team of doctor’s including Henna Kärkkäinen, MD, Ph.D, Department of Gynecology and Obstetrics, Heikki Matero Ph.M, Janne Sahlman MD, Ph.D at the Kuopio University Hospital.  The study concludes that an on-demand reminder system increases adherence of birth control pill users. More details regarding this study can be found here. )

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