FAQs about birth control

What medications interact with my birth control?

Because there are so many birth control options and so many other medications, it isn’t possible to list all of them. To be safe, let your doctor and pharmacist know about all of the medications you take, even over the counter medications and medications you may get from a different pharmacy. Condoms and ParaGard (the copper IUD) are the only contraceptive options that have no medication interactions.

What should I do if I miss a dose of my birth control pill?

This can vary depending on the exact birth control pill you are taking, how many doses you missed, which week in the cycle you are in, and when you last had sexual intercourse that could result in pregnancy. However, here are some rules of thumb:

  • If you take a COC and it has been less than 2 days, take it as soon as you remember. If it has been more then 2 days, use backup contraception such as condoms for one week, and if you have had intercourse that could result in pregnancy in the last 5 days, consider use of emergency contraception such as Plan B.
  • If you take a progestin only pill, check with your pharmacist as each one has different recommendations. Depending on how long it’s been since you took a dose they may recommend back up contraception for 2-7 days.
  • For a more detailed version, check the paperwork that comes with your birth control, ask your pharmacist, or visit this patient-friendly tool for determining if your birth control is still effective: https://www.sexandu.ca/sos/sos.php
What other uses are there for birth control besides preventing pregnancy?

Besides avoiding pregnancy, some patients take birth control to get rid of or lessen their periods, or to treat acne or symptoms of hormonal imbalances like PCOS, among others. 

What are the side effects of birth control?

Side effects will vary from person to person and between the different forms of birth control. Generally speaking, oral contraceptives may cause nausea or vomiting, patches may cause skin irritation where they are applied, and most hormonal birth controls will stop or lessen period symptoms to some degree. Most side effects will go away after a few months. Here are a few examples of common side effects and things you can do to help you deal with them:

  1. Nausea: take the medication with food
  2. Skin irritation: rotate where you apply the patch. One patch might go on your left arm, the next on your right, etc.
  3. Irregular bleeding: There are two main ways to combat this.
    1. Do not skip the placebo week. In other words, let yourself have a regular period. While this will result in bleeding, at least it will be predictable.
    2. Skipping the placebo pills for as long as you don’t want a period. This one will take longer to completely get rid of spotting, so you may continue to see spotting for up to a few months if you choose to go this route.
What is a “placebo” week?

Most birth control pills come in a packet containing 3 weeks of “active” pills and 1 week of “placebo” pills. This is meant for you to be able to get your period as some peace of mind that you are not pregnant. Some birth controls come in 3-month packs of 11 weeks of active pills and 1 week of placebo. During the placebo week, you can either take the placebo pills, which contain no contraceptive but may contain iron to help with your period, or discard the pills. This will have no effect on how well the active pills work. Of note, if your doctor prescribed you a birth control that has iron in the placebo pills, this is likely to help replace iron lost in your period. Talk with your doctor about whether they recommend you take them if you choose to get your period. Make sure everyone (you, your doctor, and your pharmacist) is on the same page regarding if you are or are not taking your placebo pills. This is important for your care and to ensure your insurance covers the medicine.

Is it safe to delay or avoid my period indefinitely?

Unless you have been told by your doctor that you should get your period every month, it is safe to skip the placebo week and go straight to the next pack. You can do this indefinitely, or you can simply delay it for a week if, for example, you are going on vacation and don’t want to deal with your period. Skipping the placebo week may result in some light spotting, especially when you do it for the first time or if you haven’t done it in a while. Just make sure to tell your doctor that you want to do this, so that they can prescribe you enough refills and you won’t run out of pills too soon!

How long will it take to work?

This depends on when you start your pill in relation to your cycle. Generally speaking, if you start the contraceptive on the first day of your period, you are fully protected immediately. If you start it at another point in your period, you may have to use a backup method of birth control for up to 1 week or avoid vaginal sex in that time.

Prepared by Aimee Marentette PharmD Candidate 2026

References: