Do you ovulate on birth control?

Hormonal birth control stops ovulation, meaning your ovaries won’t release an egg. It’s the main way all kinds of hormonal birth control prevent pregnancy, and it’s one of the reasons these kinds of contraception are so effective.

But because ovulation isn’t really something you can feel, it’s pretty natural to wonder if hormonal birth control is doing its job. The bleeding that can accompany hormonal birth control can make it seem like you’re getting your monthly period, too, which can add to the confusion (spoiler: it’s called withdrawal bleeding, and is not technically your period).

Thankfully, decades of studies show that hormonal birth control is safe and highly effective at preventing pregnancy, meaning it works more than 99 percent of the time when used correctly.¹ Options like the birth control pill, patch, intrauterine device, ring, and more all keep you from getting pregnant by delivering sex hormones that stop your ovaries from releasing an egg.² Non-hormonal contraception like condoms and the copper IUD also prevent pregnancy, but they don’t stop ovulation.^2-3

So what’s going on inside your body when you’re on hormonal contraception? And what if you do happen to ovulate while taking hormonal birth control? Read on for the answers!

How does hormonal birth control stop ovulation?

Ovulation is when your ovaries release an egg, and it typically happens about 14 days into your menstrual cycle, though the exact day can vary a bit. It’s a carefully orchestrated process that’s cued by a few different hormones.⁴

First, gonadotropin-releasing hormone (GnRH) causes the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH tells a follicle, a small sac that contains an egg, to begin to mature, and around day 14 of your cycle, a spike in LH causes the follicle to release an egg. The egg travels down your fallopian tubes for about 24 hours, a journey during which it can meet a sperm and become fertilized.⁴

Learn more about hormones and their functions.

But none of that happens if you’re taking hormonal birth control. All forms of hormonal birth control contain sex hormones that interrupt the normal signals telling your body to ovulate, meaning no egg gets released. It’s similar to the process that naturally occurs in your body to prevent ovulation during a pregnancy. (That’s why people often say hormonal birth control “tricks your body into thinking it’s pregnant.”)⁵

All hormonal birth control contains progestin, an artificial version of the sex hormone progesterone. Different kinds of birth control deliver different varieties and amounts of progestin, but they’re all highly effective at preventing pregnancy. Some kinds contain estrogen as well.^6-8

Progestin does most of the work in preventing ovulation. It inhibits the release of GnRH, which reduces the amount of FSH and LH present in your body. Without the presence of FSH and the corresponding spike in LH, follicles don’t develop, and they don’t get a signal to release an egg. Estrogen can help out by slowing the release of FSH and also inhibiting follicular development, though it’s not necessary to have it. All in all, if no egg gets released, there’s no ovulation, which means no egg to fertilize, and no possibility of pregnancy.⁵

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Are there signs of ovulation while on birth control?

With or without birth control, there aren’t any obvious signs when ovulation occurs. But there are ways to track whether it’s happening. When you ovulate, your body temperature and cervical mucus change in predictable ways⁹ — people using the fertility awareness method (FAM) of contraception often use these signs to track when they’re ovulating. (Side note: FAM is not considered highly effective contraception, and it’s quite difficult to do perfectly.)

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Can you ovulate on birth control?

Hormonal birth control is highly effective at preventing pregnancy when used correctly. If used incorrectly, which can mean missing a pill or taking it late, or forgetting to replace a patch or ring at the right time, hormonal birth control is less effective — effectiveness with “typical use” varies, but is usually between 90 and 95 percent.²

There aren’t good numbers on how likely it is to still ovulate while using hormonal birth control. They’re more than 99 percent effective with perfect use, so the probability is sure to be very small. If you miss a pill, there is a chance that ovulation could happen, though the probability depends on what pill you’re taking and what week of the pack you’re in.

For combined pills, if you miss just one day, you can catch up by taking the missed pill as soon as possible. If you miss two days of a combined pill, you may not be protected against pregnancy, and may need to use emergency contraception or another method like a condom.¹⁰ Progestin-only pills are less forgiving: If you take one more than three hours after you normally would, you might not be protected against pregnancy. You should take the pill as soon as you can, and use a condom or other supplemental method for 48 hours after that.¹⁰

Can you get pregnant on birth control?

Even if you do ovulate while on hormonal birth control, the odds of pregnancy are still low. That’s because the sex hormones in birth control have secondary effects that also make a pregnancy less likely. Progestin thickens cervical mucus, which stops sperm from getting through, and it also thins the lining of your uterus, or endometrium, to prevent an egg from implanting there.⁵

In other words, preventing ovulation isn’t the only way hormonal birth control can prevent a pregnancy. All together, these are what make hormonal birth control 99 percent effective when used correctly.

Learn more about your birth control options

Finding an effective birth control that works for you takes knowledge of both the options out there and your own body. The best place to start is with The Birth Control Test, which uses your unique biology to show you which hormonal birth control options might be a good fit for you.