Missed One Dose Of Birth Control In First Week When First Starting

The pharmacist discusses what to do if you miss a dose of birth control pills after starting them for the first time or after a long absence.

Missed One Dose Of Birth Control In First Week When First Starting
May 15, 2018

Beckyy asked

I just started taking birth control pills again and I realized I missed one in the first week, (it was missing from the pack so I thought I had taken it but I punched it out with another on accident and lost it) so I completely missed one of the first week pills. I had sex with my husband that week multiple times without any other contraceptive and it is too late now for Plan B. What are the chances of me being pregnant? Should I stop taking the pill as I already missed one of the first weeks?

Answer

Birth Control Time

Hormonal contraceptive pills, also known as birth control pills, are considered to be a very effective in preventing unwanted pregnancy, with a failure rate of 0.1% when taken correctly. It is important to note when you first start taking birth control pills (i.e. taking for the first time or after a long absence) that the effectiveness of birth control pills varies in the first week and greatly depends on when you start taking them.

I am going to review how to begin taking birth control pills because you have just restarted taking the hormonal contraceptive pill. From there, I will discuss missed doses.

How To Start Taking Birth Control

Hormonal contraceptive pills ideally should be started on the first day of the period to provide protection immediately. If you begin taking your birth control pills on the first day of your period (i.e. "Day One Starter"), most products state that you do not need to use backup contraception.

However, birth control pills are commonly initiated the Sunday following your last period. If you are a "Sunday Starter", you need to use backup contraception until you take 7 consecutive days of active pills. In other words, use another method of birth control (e.g condom) as a back-up method if you have sex anytime from the Sunday you start your first pack to the next Sunday. Back-up contraception for Sunday starters only needs to be done the first month when starting your pills for the first time or restarting after a long break. It is not necessary every month thereafter.

What To Do About One Missed Dose When First Starting Birth Control

What to do about a missed dose depends on the specific birth control product you are taking as recommendations will vary. It is important to remember however, that if you just restarted taking birth control pills after a long break and are a "Sunday Starter", you are not protected from pregnancy in the first week of your first pack (you are protected after for the subsequent packs).

If you are not a first time Sunday Starter and are a Day One Starter, most birth control products (such as Yasmin) give the following recommendation for missing one dose:

  • If you miss one dose of your pack, take it as soon as you remember. Take the next pill at your regular time. This means you may take two pills in one day.
  • You do not need to use a back-up birth control method if you have sex.


In your specific situation, you mentioned that you are restarting your birth control pills (presumably after a long absence) and you missed one dose in the first week, and you had unprotected sex.

  • If you started the birth control pack on the first day of your period ("Day One Starter"), you should be protected from pregnancy. However, you can still use back-up contraception to be safe.
  • If you started the birth control pack on the first Sunday after your period ("Sunday Starter"), you are not protected from pregnancy for the first 7 days, regardless of missed doses.
  • You should continue to take your pills daily at the same time if you missed only one dose. 

Be sure to look at the patient information for your specific birth control product in regard to what to do about missed doses as recommendations can vary.

There is no certain percentage to the chance that you could become pregnant. You may be at a higher risk for unwanted pregnancy by a missing dose (depending on the birth control product), especially if you are a "Sunday Starter" as protection is minimal in the first week. Take the missed pill as soon as possible and continue taking the remaining pills as usual. Do not stop taking your pills.

If you are worried that you have become pregnant or have a missed period take a pregnancy test to confirm. Most urine pregnancy test can be taken about 2 weeks after conception, but some tests may be more sensitive than others and can be taken earlier.

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