Do You Need Back-Up Contraception After Restarting Yaz?

In our latest question and answer, the pharmacist discusses whether or not back-up birth control is needed after restarting Yaz pills.

Do You Need Back-Up Contraception After Restarting Yaz?
Jul 06, 2020

Raj66 asked

Hey, so I started taking birth control Yaz for the first time in years. I was told to start on the first day of my period. Now, my period was due Saturday but it hadn’t actually come yet and I started it. Sunday I had some light bleeding and took the pill again at the same time as advised. That night, I had sex, we used condoms, but they kept breaking and there was a point that we had unprotected sex (but not for long and there was no ejaculation). I realize I am extremely paranoid but my question is should I be worried? I am considering getting a morning-after pill? Is that crazy?

At a glance

  • You are not crazy for worrying and seeking answers about pregnancy prevention.
  • The chances of getting pregnant from unprotected sex if your partner did not ejactulate are rare but possible.
  • The Plan B pill is proven most effective if it can be used within 72 hours of unprotected sex.


Hi Raj and thank you for your question. First off, I would like to assure you that you are not crazy for worrying. It is normal to have questions when starting a new medication and it is always rational to seek advice about pregnancy prevention. When trying to prevent pregnancies, it is definitely better to be cautious.

To start, based on that information you told me, it is unlikely that you would become pregnant from the events you described. It is rare, but possible to become pregnant from pre-ejaculate or semen remaining from the previous ejaculation. 

Yaz (or its generic name drospirenone and ethinyl estradiol) is used as an oral contraceptive regimen to prevent pregnancy. There are two ways to start taking the pills:

  • Day One Method: Start on the day you get your period
  • Sunday Start Method: Start on the Sunday following your period

With the 'day one start', as long as you take a pill every day at the same time, the pills are working as they should to protect you from pregnancy. There is no need for backup contraception if you are sexually active according to the FDA-approved drug information.

With the 'Sunday start', you do need to take pills 7 days in a row to be considered protected from pregnancy and should, therefore, you backup protection if you are having sex.

Now, you've described starting your pills on the day you were supposed to get your period. This would be a 'day one start' and you should be protected.

However, you mentioned you didn't actually get your period that day, so you could technically say it was not a 'day one start'.

As a general recommendation, to be as safe as possible, if you start Yaz later than the first day of your period (which perhaps happened in this case, we don't's not unheard of to have a period but not bleed) you should use another method of birth control (such as a condom) as a back-up method until you have taken 7 days of active pills.

Plan B (or its generic name levonorgestrel) is commonly referred to as “the morning after pill”. It works to lower your chances of getting pregnant after unprotected sex by preventing ovulation or fertilization. This medication should be taken as soon as possible after unprotected sex and is more effective the sooner you take it. It is recommended to be used within 72 hours of unprotected sex but is still considered moderately effective if used within 5 days.

Given this information, it’s up to you regarding the use of Plan B. The risk of pregnancy is low, but not zero. You, more likely than not, did start taking your pills on the first day of your period but we can't be absolutely sure, so I don’t think that you are crazy to take a dose of Plan B. You can continue to take your Yaz birth control as prescribed at the same time each day even if you decide to take Plan B pill. If your next period is over 1 week late, I would recommend taking a pregnancy test at that point. 

  • Plan B Prescribing Information, FDA
  • Yaz Prescribing Information, FDA

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