You’re staring at a tiny plastic T-shaped device in a pamphlet at the doctor's office, or maybe it’s already tucked away inside your uterus. One of the biggest questions people have—and honestly, one that many doctors gloss over with a quick "it just works"—is do you ovulate with Mirena IUD?
The short answer? Probably. But also, maybe not.
It’s complicated. Unlike the combined oral contraceptive pill, which is designed to shut down the communication between your brain and your ovaries entirely, the Mirena operates on a much more localized level. It’s a bit of a maverick in the birth control world. It focuses its energy on the uterus rather than just overriding your entire endocrine system.
Let's get into the weeds of why your body might still be releasing eggs even though you’re technically on "hormonal" birth control.
The Localized Effect vs. Systemic Control
The Mirena is a levonorgestrel-releasing intrauterine system (LNG-IUS). It pumps out a steady, low dose of a progestin. Most people assume that "hormonal birth control" automatically means "no ovulation." That’s a massive misconception.
With the pill, hormones flood your bloodstream. They tell your pituitary gland to take a nap. No FSH (follicle-stimulating hormone). No LH (luteinizing hormone) surge. No egg.
Mirena plays a different game.
The hormone levels in your blood with a Mirena are actually quite low—significantly lower than what you’d find in someone taking a daily pill. Because the device is sitting right there in the uterine cavity, the levonorgestrel mostly stays put. It thickens the cervical mucus so sperm hit a brick wall. It thins the uterine lining so nothing can plant itself there. But the ovaries? They often just keep doing their thing.
Research published in the journal Contraception and data from the manufacturer, Bayer, shows that in the first year of use, about 85% of cycles are still ovulatory. By the time you've had it for four or five years, that number actually climbs. Your body adjusts.
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Why Do Some People Stop Ovulating Anyway?
If the hormone dose is so low and localized, why do some people stop ovulating?
It’s about individual sensitivity. Every body reacts to levonorgestrel differently. For a subset of users, even that tiny bit of systemic hormone is enough to tip the scales and suppress the ovarian cycle.
In the beginning—usually the first year—your body is getting the highest dose the device will ever emit. Mirena starts by releasing about 20 micrograms of levonorgestrel per day. Over five to eight years, that rate slowly drops to around 7 to 10 micrograms. This is why many women find their periods disappear or become irregular in year one, but then they might see a "return" of symptoms later on.
It’s not that the IUD is "failing." It’s just that the hormonal influence on the ovaries is weaning, while the local effect on the uterus remains strong enough to prevent pregnancy.
The Confusion of the "Phantom Period"
If you're wondering do you ovulate with Mirena IUD because you still feel "PMSy" but don't bleed, you aren't crazy.
This is the classic Mirena paradox.
You might experience breast tenderness, mood swings, or even that distinct "ovulation pain" (mittelschmerz). This happens because your follicles are still growing. Your estrogen is still rising and falling. You are having a hormonal cycle. However, because the IUD has thinned your endometrium (the lining of the uterus) to almost nothing, there is nothing to shed.
No blood doesn't mean no cycle.
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It’s a strange feeling. You feel the bloat. You feel the crankiness. You check the calendar. But the "period" never shows up. For many, this is the "Goldilocks" zone of birth control—all the protection, none of the laundry-ruining mess.
What the Clinical Data Actually Says
Let’s look at the numbers. Dr. Luukkainen, one of the original developers of the LNG-IUD, noted in longitudinal studies that ovarian function remains largely intact for the vast majority of users.
- Year 1: Roughly 15% of cycles are anovulatory (no egg released).
- Year 4+: Less than 5-10% of cycles are anovulatory.
Basically, if you’ve had your Mirena for a while, you are almost certainly ovulating.
This is also why Mirena is often better for libido than the pill. Because you aren't suppressing your natural testosterone and estrogen fluctuations as aggressively, many people find they maintain their "natural" drive better than they did on oral contraceptives.
Ovarian Cysts: The Side Effect Nobody Explains
There is a specific side effect related to this. Because Mirena doesn't always stop follicle development, sometimes those follicles get a little... overexcited.
They grow, but they don't always rupture and release the egg on time. This leads to "enlarged follicles" or functional ovarian cysts. According to the FDA-approved prescribing information, these occur in about 12% of Mirena users.
Usually, they’re harmless. They disappear on their own in a month or two. But if you feel a sharp tugging in your lower abdomen, that’s your ovary doing its job under the influence of the IUD. It's a sign that you are indeed ovulating (or trying to).
How to Tell if You are Ovulating on Mirena
You can't rely on a bleed. So, how do you know?
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- Basal Body Temperature (BBT): If you are dedicated enough to track your temp every morning before getting out of bed, you’ll see the shift. A spike in temperature after the middle of your cycle confirms progesterone is present, which means you ovulated.
- Cervical Mucus: This is trickier because Mirena thickens the mucus as its primary job. However, some people still notice a change in consistency around mid-cycle.
- Hormonal Symptoms: Acne flares, libido spikes, and breast heaviness are clues.
- LH Strips: You can use over-the-counter ovulation predictor kits. If you get a "peak" reading, your brain is sending the signal to release an egg.
Does it Matter?
For pregnancy prevention? No.
Mirena is 99% effective regardless of whether you ovulate. It’s a multi-layered defense system.
But for your health? It might.
There is a growing body of thought in functional medicine, often discussed by experts like Dr. Lara Briden (author of Period Repair Manual), that ovulation is about more than just making babies. Ovulation is how our bodies produce progesterone. Progesterone is great for bone health, skin, and anxiety management.
If you are one of the people who does continue to ovulate with a Mirena, you’re getting the "progesterone hit" from your own body, plus the contraceptive benefits of the device. It’s kind of the best of both worlds.
On the flip side, if the Mirena suppresses your ovulation and you feel flat, depressed, or lose your hair, it might be because your body is sensitive to that specific progestin and isn't making its own hormones to balance things out.
The Takeaway
Most Mirena users continue to ovulate.
The idea that all hormonal birth control stops your cycle is an old-school myth that ignores how IUDs actually work. If you have a Mirena, you are likely still a "cycling" person; you just don't have the uterine lining to show for it.
Actionable Insights
If you’re trying to track your health while on Mirena, don't look at the toilet paper for blood. Start a symptom journal.
- Track your mood and skin. Do you get a pimple on your chin every 28 days? That’s an ovulatory cycle.
- Don't panic about "missing" periods. If you've confirmed you aren't pregnant, amenorrhea (lack of bleeding) is a normal, intended effect of the levonorgestrel on your uterine lining.
- Watch for persistent pain. If you have localized pain on one side of your pelvis that lasts more than a few days, see your GP for an ultrasound to check for those common functional cysts.
- Check your strings. Knowing whether you're ovulating is cool, but knowing your IUD is still in place is more important for the "not getting pregnant" part of the equation.
The Mirena is a "set it and forget it" tool, but your endocrine system is never truly "off." Understanding that you are likely still ovulating can help you make sense of why you still feel like a different person at different times of the month.