I Started Birth Control Today—So When Does It Start Working?

Clinically Reviewed By: Lisa Czanko, MD, MPH

We love instant gratification as much as the next person, but some things are simply worth a little bit of a wait. A pot of chili simmering on the stove all day, taking the scenic route to your local hiking spot, saving your pennies for the latest skincare fad—they’re all made sweeter knowing that your patience paid off.

Another instance of delayed gratification? Knowing that your hormonal birth control is doing its job preventing pregnancy. Here’s how long it takes different types of hormonal birth control to become effective.

How long does it take hormonal birth control to start working?

Timing is everything, as they say. The date your hormonal birth control starts being effective at preventing pregnancy depends on the specific type of birth control you’re using and when during your cycle you start using it. In general, it’s going to be a few days—so make sure you’re stocked up on barrier methods in the meantime. 

How long does it take the pill to start working?

If you start taking combination pills made up of estrogen and progestin within five days of starting your period, you’ll be protected from pregnancy right away. So, if you start your period on the morning of the 1st, you can start taking the combination pill at any point until the morning of the 5th, and you’ll be protected from pregnancy. 

Why the five-day rule? It all goes back to your menstrual cycle. Day 1 of your menstrual cycle is the day you start your period. Most people ovulate between days 11-21 of their cycle. During this time around ovulation, you have the highest chance of getting pregnant—and that fertile window starts a few days before ovulation, since sperm can survive inside your body for up to five days. When you’re on your period, your egg is discarded along with the lining of the uterus. So, being on your period means you’re most likely not within your fertile window, meaning it’s the right time to start your hormonal birth control. 

However, if you start taking your pill at any other time, it takes around seven days for birth control to become effective. So, bust out a backup method if you plan to have vaginal sex while starting birth control—just in case. 

If you start taking progestin-only minipills within five days of your period starting, they're effective immediately. If you start the minipills at any other time in your cycle, use a back-up method of contraception or abstain for two days.

With perfect use, birth control pills are 99% effective at preventing pregnancy, but with typical use, that drops to 91%. This means that you have to take your pill consistently every day, for the most effective results. 

How long does it take the patch to start working?

The timing for the patch is the same as it is for the combination pill (makes sense, since the patch releases estrogen and progestin to prevent pregnancy). Start your patch within the first five days of your period, and you’re protected right away. Start the patch at any other time in your cycle, and it takes seven days to become effective. BTW, the patch is 93% effective with typical use but with perfect use the patch is 99% effective. 

How long does it take the ring to start working?

For your vaginal ring to be effective right away, you need to insert it within the first five days of your period. If you insert the ring at any other point in your cycle, it takes seven days to work. With perfect use, the ring (which releases estrogen and progestin to prevent ovulation) is 98% effective at preventing pregnancy. Most rings will not last longer than one cycle and require a new ring to be effective. An exception is Annovera, a ring that you can reuse all year long. If you insert Annovera between days 2 and 5 of your period, it becomes effective on the day that it is inserted. However, if Annovera is inserted more than five days from when you started your period, it becomes effective seven days after you insert it. Say it with us now: during those seven days, you should also use another form of backup contraception to prevent pregnancy.When used correctly, Annovera is 97.3% effective.

No matter what type of birth control you’re using, it’s smart to consult with your doctor about how long it’ll take for your birth control to be effective. Got specific questions? Reach out to our Care Team for support.

Citations:

U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. https://www.cdc.gov/mmwr/volumes/65/rr/pdfs/rr6503.pdf. 

“Contraception.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 13 Aug. 2020, https://www.cdc.gov/reproductivehealth/contraception/index.htm. 

“Get Answers to Commonly Asked Questions about ANNOVERA® Contraceptive Ring: Therapeuticsmd.” Get Answers to Commonly Asked Questions about ANNOVERA® Contraceptive Ring| TherapeuticsMD, https://www.annovera.com/faq.