Mirena: The Contraceptive That Is Also a Treatment

There is a device that reduces menstrual blood loss by more than 70%, treats adenomyosis, reverses a pre-cancerous thickening of the uterine lining better than tablets do, reduces endometriosis pain, protects the lining during HRT, and happens to be one of the most reliable contraceptives ever made. In India, most women have never had it properly explained to them.

Part of the reason is structural. The copper IUCD is in India's national family planning programme; the hormonal one is not. It is a private-sector device, so it is rarely mentioned in the places where most women first hear about contraception, and when it does come up it is presented purely as birth control.

That framing sells it short. This page is about everything else it does — and about the two questions women ask me most often and rarely get a straight answer to: will it make me depressed, and does it cause breast cancer. Both are answered honestly further down, with numbers.

What is the Mirena, and how is it different from a Copper-T?

Both are small devices placed inside the uterus, and both are fitted the same way. There the similarity ends.

A Copper-T releases no hormone. Copper ions make the uterus an inhospitable place for sperm. It works immediately, lasts 5 or 10 years depending on the device, and typically makes periods heavier.

A Mirena releases a small amount of levonorgestrel — a progestogen — directly into the uterine cavity. Because the hormone is delivered where it is needed, very little circulates around the rest of the body. It thickens cervical mucus so sperm cannot get through, and it keeps the lining of the uterus thin. That thin lining is the whole reason it works as a treatment, and it is why periods become dramatically lighter rather than heavier.

Our page on Copper-T, Mirena and the contraceptive implant compares all three side by side, including what each does to bleeding and how they are fitted.

How reliable is it as contraception?

Very. The real-world failure rate is about 0.2% a year — roughly one pregnancy in 500 women per year, which puts it in the same bracket as sterilisation while remaining completely reversible.

It takes seven days to become effective unless it is fitted within the first seven days of your period, in which case it works straight away. It can be fitted at any point in the cycle as long as pregnancy can reasonably be excluded — you do not need to wait for your period.

After removal, fertility returns immediately. The pregnancy rate in the year after removal is the same as in women who were using no contraception at all.

The part most women are never told: it is a treatment

Here is what the guidelines actually say.

NICE, in its guidance on heavy menstrual bleeding, recommends considering the hormonal coil as the first treatment for heavy periods in women with no identified pathology, or with fibroids under 3 cm that are not distorting the uterine cavity, or with suspected or diagnosed adenomyosis.

FOGSI, India's own federation of obstetric and gynaecological societies, goes further and recommends it across most categories of abnormal uterine bleeding — grading it Level 1, Grade A evidence for adenomyosis and for endometrial hyperplasia.

What follows is what it does in each situation, and how strong the evidence actually is in each case — because it is not equally strong everywhere.

Heavy periods: how much difference does it really make?

A large amount, and quickly. Menstrual blood loss falls by 62 to 94% within three months and 71 to 95% within six months. Most of the improvement is achieved in the first three months.

Pooling 25 randomised trials in more than 2,500 women, the hormonal coil reduced blood loss substantially more than other medical treatments, and treatment failure was about two-thirds lower.

Indian data mirror this closely. In a study of 60 women at a Delhi hospital, bleeding scores fell by 95% in women with dysfunctional bleeding and 97.7% in women with fibroids over nine months, with significant rises in both haemoglobin and ferritin. A Maharashtra series found haemoglobin rising from 9.4 to 11.6 g/dL, with 93% of women still using the device.

That haemoglobin point matters more than it sounds. A great many Indian women with heavy periods are quietly anaemic and have been for years, and correcting the bleeding corrects the anaemia in a way iron tablets alone rarely manage.

If heavy bleeding is your problem, our guide to heavy and irregular periods and when to consider surgery works through the whole ladder of options in order, from tablets through to the operations.

Will it save me from a hysterectomy?

I want to answer this carefully, because the honest answer is more complicated than the one usually given, and you deserve the complicated one.

The encouraging evidence. In a randomised study of 56 women who were already on a hospital waiting list for hysterectomy because of heavy bleeding, 64% of those given a hormonal coil cancelled their surgery within six months, against 14% of the control group. Nearly half were still using the device three years later.

The evidence that complicates it. A much larger UK trial — 571 women, followed for ten years — compared the hormonal coil against usual medical treatment in general practice. Quality of life improved significantly more with the coil, and at five years 47% of women were still using it against 15% still on their tablets. But the rate of hysterectomy was no different between the groups at two, five or ten years. And when the coil is compared against endometrial ablation rather than tablets, slightly more women go on to have a hysterectomy after the coil.

These findings do not collapse into a single slogan. What I take from them, and what I say in clinic:

If an operation has been recommended to you, our guide to hysterectomy and when it is genuinely needed is worth reading before you consent to anything.

Adenomyosis

This is one of its strongest uses, and one of the few good options for a condition that is otherwise difficult to treat without removing the uterus.

In adenomyosis, lining tissue grows into the muscle wall of the uterus, producing heavy bleeding with severe cramping that has usually worsened over years. In a recent study of 110 women with adenomyosis, six months after fitting: menstrual loss fell from about 67 mL to under 5 mL, period pain scores fell from 5.5 to 1.4 out of 10, 53% had complete relief of period pain and 81% had some improvement. Satisfaction was 87%.

One honest caveat. The device does not appear to shrink an adenomyotic uterus, and in that study the few devices that were expelled were all in women with markedly enlarged uteri. If your uterus is very bulky, the coil is more likely to come out, and you should be told that before it is fitted rather than after.

Fibroids: where it helps, and where it does not

This section exists because the distinction is constantly blurred, including by people who should know better.

The Mirena does not shrink fibroids. A study of 68 women with fibroids inside the uterine cavity found bleeding scores down by 88% at a year — and no measurable effect on either fibroid volume or uterine volume. It treats the symptom, not the growth.

Where it works well: small fibroids that are not distorting the cavity, in a woman whose main complaint is bleeding. Where it works badly: fibroids that push into or distort the cavity. A distorted cavity is an outright contraindication, because the device will not sit properly and will be expelled. In that Delhi study, treatment failure was 3.4% in women with no structural cause but 23.3% in women with fibroids — a sevenfold difference that is worth knowing before you pin your hopes on it.

There is also a genuine guideline disagreement here that nobody mentions to patients: NICE draws the line at fibroids under 3 cm, while FOGSI is willing to try up to 4 cm in women over 40 who have completed their family — though FOGSI grades that recommendation more weakly than its others. In practice, the size matters less than whether the cavity is distorted, which is a question for a scan.

Our guide to fibroids and whether they actually need surgery explains why location matters more than size, and how the different operations compare.

Endometrial hyperplasia: the strongest indication of all

If the lining of the uterus becomes too thick — usually from years of oestrogen without enough progesterone — that is endometrial hyperplasia. Left alone, a proportion of cases progress towards cancer, so it is treated rather than watched.

For hyperplasia without atypical cells, the RCOG's position is unambiguous: the hormonal coil should be the first-line medical treatment, because it produces higher regression rates than progesterone tablets with a better bleeding pattern and fewer side effects. The advantage widens the longer treatment continues — the odds of regression with the coil versus tablets are more than five times higher at twelve months, and more than seven times higher at two years.

Getting that biopsy properly is part of the treatment. A blind sample misses focal disease, which is why sampling is best done under direct vision — the reasoning is set out in our guide to hysteroscopy and why it is not the same as a D&C.

Endometriosis

The European guideline gives a strong recommendation for the hormonal coil to reduce endometriosis-associated pain. It also recommends it after conservative surgery — kept in for at least 18 to 24 months — to prevent period pain coming back.

Note the precision there: the post-surgical recommendation is specifically about preventing the return of period pain, not all endometriosis pain and not anatomical recurrence. It is a good option, not a cure.

If painful periods are your problem, start with our guide to endometriosis and why painful periods are not normal — it includes a symptom checklist worth taking to your appointment.

PCOS and infrequent periods

Here I have to be straight with you, because this is a place where clinic pages routinely overstate things.

If you have PCOS and ovulate rarely, your uterine lining is exposed to oestrogen for long stretches without the monthly progesterone that would normally shed it cleanly. Over years, that raises the risk of the lining becoming too thick. Protecting the endometrium is a real and recognised part of PCOS care.

But the 2023 international PCOS guideline recommends regular progestogen therapy without specifying a formulation or a route — it does not mention the hormonal coil at all. So using a Mirena for endometrial protection in PCOS is a reasonable extrapolation from the hyperplasia evidence above, and a very practical one for a woman who does not want to take tablets for years. It is not, however, something a PCOS guideline tells you to do, and I would rather you heard that from me than discovered it later.

Our article on the seven signs a doctor looks for in PCOS covers what a proper assessment involves.

Around the menopause and with HRT

If you take oestrogen as HRT and still have a uterus, you need a progestogen to protect the lining. The Mirena is the only intrauterine device licensed for that purpose, and it has the advantage of dealing with heavy perimenopausal bleeding at the same time.

Two practical points. The UK licence for this particular use is four years, although the British Menopause Society notes that five years is common and safe practice, and says so explicitly. And if it is fitted in your forties, the five-year review is usually the point at which we talk about where you are in the menopause and whether it needs replacing at all — for a good number of women, one or two fittings see them through to the other side of it.

What will my periods actually do?

This is the question that decides whether women keep the device, so it deserves specifics rather than "it settles down".

The single commonest mistake is judging the device at six weeks. If you can give it six months, the odds are strongly that you will be glad you did. If you want it out before then, that is your decision and it should be removed without argument — but do make the decision knowing the timeline.

What are the side effects?

The ones listed as common — meaning between 1 in 100 and 1 in 10 women — are acne, headache, breast tenderness, low mood and reported weight increase. Hair thinning is uncommon. Most hormonal side effects are worst in the first few months and settle.

Two that come up constantly:

• Ovarian cysts. Small fluid-filled follicles are reported in about 7% of users. Most cause no symptoms, and most disappear on their own within two to three months. They are not a reason to remove the device. If you have been told a scan shows a cyst, our guide to ovarian cysts and when they need surgery explains which kinds matter.
• Weight. Weight increase is reported commonly, but studies do not show that intrauterine contraception actually causes weight gain. Reported and caused are not the same thing, and the distinction is worth holding on to.

Does the Mirena cause depression?

This deserves a proper answer rather than either a dismissal or a scare.

A very large Danish study of over a million women found that users of hormonal contraception were more likely to be prescribed an antidepressant, and for the hormonal coil specifically the increase was about 40% in relative terms — higher in teenagers. Those relative numbers sound alarming until you see the absolute ones: roughly 2.2 versus 1.7 women per 100 per year starting an antidepressant.

There is a serious problem with reading that as cause and effect, and the study's own authors said so. Women are given a hormonal coil because they have heavy bleeding, severe period pain or endometriosis — all conditions independently linked to low mood. And women on any contraceptive see doctors more often, so their symptoms are more likely to be picked up.

A more recent Danish study of nearly 150,000 first-time users with no previous mental health history found the absolute risk of a depression diagnosis in the first year was between 1.2% and 1.8% depending on the hormone dose. But that study compared doses against each other, not against women using nothing — so it cannot tell you the risk compared with having no device.

Where the specialists land: the UK's Faculty of Sexual and Reproductive Healthcare states that the evidence is too limited to confirm or exclude a causative effect. That is also my position. Low mood is a recognised, listed side effect; whether the device causes depression is unresolved.

What I would say practically: if you have a history of depression, that is a reason to discuss it and to keep an eye on things, not a reason to rule out the device. And if your mood changes noticeably after fitting, that is worth taking seriously and acting on rather than being told it is coincidence.

Does it increase the risk of breast cancer?

Most clinic pages do not go near this question. I would rather answer it, because the honest answer is more reassuring than a silence that leaves you to imagine the worst.

There is a small signal, and it is real. The manufacturer's own information states that the risk with progestogen-only methods including the Mirena is possibly similar in magnitude to that seen with the combined pill. A large Danish study found breast cancer about 21% more likely in relative terms among hormonal coil users than in women who had never used hormonal contraception. A 2024 study looking specifically at hormonal coil users found a similar order of increase.

Now the absolute numbers, which are what actually matter. Across all hormonal contraception, that translates to roughly one extra breast cancer diagnosed for every 7,690 women using it for a year. In the 2024 analysis, the excess was around 14 extra cases per 10,000 women over up to five years of use. Notably, when the researchers tested whether the risk rose steadily with longer use, that trend was not statistically significant — and they themselves wrote that the lack of a dose-response might indicate no causal association at all.

Risk also falls after stopping, and no increased risk was found in women who had used hormonal contraception for less than five years in the past.

The FSRH's counselling position, which I follow, is that there appears to be a possible small increase in breast cancer risk with current or recent use, and that the absolute risk remains very small — to be weighed against highly effective contraception and, in many of the women reading this, genuine treatment of a condition that is affecting their life.

If you have a personal history of breast cancer, hormonal methods are not appropriate and a copper device is usually the better answer. If you have a family history, it is a conversation worth having properly rather than a reason to rule anything out by yourself.

What can go wrong with the device itself?

• Expulsion — about 1 in 20. Most in the first year and particularly the first three months. More likely with a bulky uterus, fibroids, heavy periods, or fitting soon after delivery. This is why you are taught to feel for the threads.
• Perforation — about 1.4 per 1,000 fittings. Higher if fitted soon after delivery, especially while breastfeeding, which is why timing is discussed rather than assumed.
• Pelvic infection — under 1%, and the small extra risk is confined to roughly the first three weeks after fitting. Routine antibiotics are not given because they do not help.
• Pregnancy — about 0.1% a year. Rare. But if a pregnancy does happen with a device in place, the chance of it being ectopic is higher than usual, so a positive test on a Mirena needs prompt assessment rather than reassurance.

How long does it last, and when should it come out?

The licensed durations differ by what it is being used for: up to 8 years for contraception, 5 years when it is treating heavy periods, and 4 years for endometrial protection with HRT.

In practice, I advise all my patients to plan on 5 years. There are two reasons. It is the licensed duration for every use other than pure contraception, so it holds whatever your reason for having it. And it gives you one date to remember rather than three, with a review at five years to decide whether to replace it, switch, or stop — which is a better conversation than quietly running past a date nobody wrote down.

If it is fitted at or after 45, it can generally stay in for contraception until you are 55. It can be removed whenever you want it out — removal takes seconds and needs no anaesthetic. One practical point: avoid unprotected sex in the week before a planned removal, since sperm can survive that long and you would not be covered once the device is gone.

Getting a Mirena in Gurugram

Fitting and removal are both done at the clinic. There is no hospital admission, no anaesthetic and no cuts — you can read what the appointment involves on our page about Copper-T, Mirena and implant fitting.

Before anything is fitted, the useful conversation is about why. If the Mirena is for contraception, the choice is between it, a copper device and the implant, and that depends largely on what you want your periods to do. If it is being used as a treatment, the first question is what is causing your bleeding — because a polyp, a submucous fibroid or a thickened lining each change the answer. That means an examination and a scan, arranged at the right point in your cycle. Scans are done by referral; bring the report and images back and we will go through them with you.

Our two clinics — Sector 51 (Mayfield Garden) and Sector 56 — see patients from across Gurugram, Golf Course Road, Golf Course Extension, Sohna Road, the DLF Phases, South Delhi and nearby NCR, 7 days a week including Sundays. You can also read about the wider range of women's health care and gynaecological surgery we provide.

The bottom line

The Mirena is a contraceptive that is also, and often more importantly, a treatment. For heavy periods, adenomyosis and a thickened uterine lining it is what the guidelines say to try first — not what you resort to when everything else has failed.

It is not magic. It does not shrink fibroids, it will not certainly spare you an operation, and it will make your bleeding unpredictable for three to six months before it makes it better. The mood and breast-cancer questions have small, real, honestly-quantified answers rather than either nothing to see or a reason to panic.

What it does offer is this: a five-minute procedure, no anaesthetic, reversible the day you change your mind, that for a great many women replaces years of heavy bleeding, anaemia and daily tablets. If nobody has put it on the table for you, ask why.