Is It True You Need To Wait One Week After Starting Birth Control Pills To Be Protected From Pregnancy?

In our latest question and answer, our pharmacist discusses how soon you are protected from pregnancy after starting birth control pills.

3 min read Updated Jun 2026 Read by 4,077 people
Is It True You Need To Wait One Week After Starting Birth Control Pills To Be Protected From Pregnancy?
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Micky asked

I recently started taking the contraceptive pill, and was told that you need to take it for a week before having unprotected sex. I started the pill on Wednesday 5/03/23 and had unprotected sex yesterday (Wednesday 5/10/23). Although it has been a week since I started the pill, I didn't take the 7th dose until after I had sex yesterday. So, in reality, I had only taken the pill for 6 days before having sex. Is there still a high risk of me being pregnant?

May 11, 2023
The quick answer
  • Whether you need to wait one week depends on when you started taking your pills relative to your period. If you started on the first day of your period, you're protected right away, but if you started on any other day, you should wait seven days of taking pills consistently before relying on them for pregnancy protection. Using a backup contraceptive method is recommended until you've taken your pills for seven consecutive days if you didn't start on day one of your period.
A quick summary of Dr. Brian Staiger, PharmD's full answer below, condensed by AI from that answer only (not from any outside source). The pharmacist's answer is the source of record.

Answer

The answer to the question of whether or not you need to wait one week before having unprotected sex after starting birth control pills for the first time (in regard to being protected from pregnancy) depends entirely on which day you started your pills.

There are two different ways to start taking oral birth control pills:

  • Sunday Start
  • Day One Start

If you are a 'Sunday Starter', you are not immediately protected against pregnancy and you should wait one week after starting to consider the pill an effective contraceptive.

If you are a 'Day One Starter', you are immediately protected against pregnancy if you start taking the pill on the first day of your period. 

Difference Between The Methods

Sunday Start Method: This method involves starting the pill on the first Sunday following the start of your period.

For example, if your period started on a Wednesday, you would wait until the following Sunday to start taking the pill.

The Sunday start method is convenient for many women because it allows them to associate taking the pill with a specific day of the week. However, it does require waiting until the first Sunday following the start of your period to begin taking the pill, which can be inconvenient if your period does not align with the Sunday start.

Additionally, if the first day of your period is not Sunday, you do not have immediate protection against pregnancy.

Day One Start Method: The Day One start method involves starting the pill on the first day of your period.

The Day One start method is convenient for women whose period does not align with the Sunday start. It also provides immediate protection against pregnancy if started on the first day of the menstrual cycle. However, it may be difficult to remember the exact day of the month to start taking the pill with this method.

Additional Information

You stated in your question you started your birth control pills on Wednesday.

If that was the first day of your period (which would be considered a day one start), you are immediately protected from pregnancy.

However, if that was not the first day of your period, the general recommendation is that your birth control pills should not be considered effective as a contraceptive until after the first 7 consecutive days of product administration.

I don't know which group you fall into here...If Wednesday was not the first day of your period, having only taken 6 consecutive days of pills, you technically would be considered at a higher risk of pregnancy, although that risk would still be quite low. Regardless, back-up methods would be recommended until you reach that 7 day mark.

Final Words

I hope you found this helpful! Please contact us again anytime.

References & sources
  1. Yasmin Prescribing Information — AccessFDA
  2. Contraception Update: Oral Contraception — PubMed
Glossary — Terms in This Answer
Oral birth control pills
Medications taken by mouth that contain hormones to prevent pregnancy.
Contraceptive
A method or substance used to prevent pregnancy.
Menstrual cycle
The monthly process in a woman's body that prepares for or results in pregnancy, typically lasting about 28 days.
Product administration
The act of taking or using a medication as directed.
Back-up methods
Additional contraceptive techniques used alongside primary birth control for extra pregnancy prevention.
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Dr. Brian Staiger, PharmD
About the pharmacist

Dr. Brian Staiger, PharmD

Clinical Pharmacy

Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified

Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...

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