Should I use the Mirena coil during menopause?

How does the Mirena coil affect menopause?

The Mirena coil is a long-acting reversible contraceptive (sometimes referred to as a LARC method), that can be used for five years before needing to be changed. It is a rod made of three parts and coated with a synthetic form of the hormone progesterone, called levonogestrel. The Mirena is T-shaped because it is designed to sit within the uterus (womb): the uterus is shaped a bit like an upside-down pear.

Levonogestrel is a synthetic form of progesterone, which is found naturally in our bodies, and is released daily by the Mirena in small amounts. This slow release keeps the body in a state of not being able to fall pregnant as it not only changes the quality of cervical mucous, therefore making it hostile to sperm, but also suppresses ovulation in about 15 percent of women.1

How does the Mirena coil affect menopause?

To understand how the Mirena coil could impact menopause, it is important to understand how menopause affects our hormones.

During perimenopause, there is a complex shift in hormone levels and one of the hormones affected is progesterone. Very often, levels of this hormone, along with oestrogen, start to drop, although their levels may be high initially.

Guidance recommends that treatment with hormone replacement therapy (HRT) can help improve symptoms of menopause, including hot flushes, mood swings, and vaginal dryness.2 There are different types of HRT that may be suitable for different women, but the two main hormones used are oestrogen and progestogen (a synthetic version of progesterone). HRT is available as ‘combined’ (including both oestrogen and progestogen) or oestrogen-only. As many menopausal symptoms are due to low oestrogen, HRT is the main treatment offered.

If you are taking HRT for your menopausal symptoms whilst using the Mirena coil for contraception, the Mirena can be used as the progesterone part of your treatment. This means that oestrogen-only HRT could be given in combination with the Mirena

Oestrogen however works in synergy with progesterone and it is therefore usually advisable to take both hormones together. There are certain situations where oestrogen-only HRT is recommended, including for women who have had a hysterectomy.

Progesterone works to keep levels of oestrogen balanced, which protects against the side effects of unopposed oestrogen, including the thickening of the inner lining of the uterus (also called ‘endometrial thickening’). When the lining of the uterus is abnormally thick, this is known as ‘endometrial hyperplasia’, which in some cases can lead to uterine cancer.3 One of the ways progesterone works as a contraceptive is by keeping the lining of the womb thin, therefore making it difficult for a fertilised egg to implant into the womb.

If you are taking HRT for your menopausal symptoms whilst using the Mirena coil for contraception, the Mirena can be used as the progesterone part of your treatment. This means that oestrogen-only HRT could be given in combination with the Mirena. Women using this combined treatment must have their Mirena changed every 5 years.4

The Mirena and irregular periods

Heavy periods can occur during the perimenopause and can be masked or improved by the Mirena: in fact, the Mirena is recommended as a treatment option for heavy periods.5

This is because the synthetic progesterone released by the Mirena works to keep the lining of the uterus thin, which means that there is less to shed off during your menstrual bleed. However, in the first 3-6 months following insertion of the Mirena, some women may experience irregular bleeding, but this tends to improve over time.6 Around 20% of women may still experience irregular bleeding after using the Mirena for a year, while others may stop having periods altogether (‘amenorrhea’).7

The effects of the Mirena may then also ‘mask’ the heavy periods you would otherwise experience as symptoms of menopause.

The Mirena and menopausal symptoms

If you are using the Mirena coil, it may be difficult to decipher whether your symptoms are due to you entering perimenopause or side effects of the coil.

Hormonal blood tests are sometimes used to try and identify whether you’re approaching menopause but can be difficult to interpret, as synthetic hormones affect the levels of natural hormones made by the body. If you are using the Mirena, a hormonal blood test may then not be effective and therefore not be recommended by your doctor.

These tests look at levels of hormones follicle-stimulating hormone (FSH) and lutenising hormone (LH), which are produced in the brain and provide a signal to the ovaries to produce oestrogen. As you approach menopause, levels of these hormones tend to be raised.

If you are using the Mirena and experience new symptoms, this can either mean that the coil has been dislodged, or if you are over 35, that you are entering perimenopause

A blood test can be considered if you are between the ages of 40 and 45 and have menopausal symptoms. It is definitely recommended if you have symptoms and are below the age of 40.

The symptoms of perimenopause however can be extensive and not only include the above but also breast tenderness, acne, mood disturbances, weight gain, joint discomfort, and insomnia, to name a few. Some of these symptoms are also side effects of the Mirena. Symptoms of the perimenopause have been noted to start as early as around the age of 35 and therefore symptoms before that age are more likely to be due to the Mirena.

Also, if they are due to the Mirena, these symptoms tend to improve with time and have usually settled within 3 months of use.8 If you are using the Mirena and experience new symptoms, this can either mean that the coil has been dislodged, or if you are over 35, that you are entering perimenopause.

Some of these symptoms also occur with pregnancy as hormonal shifts occur in the body during this period, so your doctor will always rule this out with a pregnancy test.

Featured image is a close-up of a woman’s face. She is resting her chin on her hand and staring into the distance. She is visible from the nose to the tops of her shoulders

Last updated January 2020
Next update due 2022

Dr. Deyo Famuboni, MB ChB

Dr. Deyo Famuboni is a UK trained GP with over 10 years of medical experience. After graduating from the University of Edinburgh, she went on to do further training within a wide range of medical specialities including obstetrics and gynaecology. She has spent time working abroad as well as within the NHS and private sectors in the UK. She is a member and clinical advisor of the Royal College of General Practitioners and a diplomate of the Royal College of Obstetrics and Gynaecology, Royal College of Paediatricians and the Faculty of Sexual and Reproductive Health. She also has a strong interest in nutrition and health.

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References

  1. NICE, ‘Contraception – IUS/IUD’, Clinical Knowledge Summary, National Institute for Health and Care Excellence, May 2019, [online] https://cks.nice.org.uk/contraception-iusiud#!scenario (accessed 27 January 2020)
  2. NICE, ‘Menopause’, Clinical Knowledge Summary, National Institute for Health and Care Excellence, March 2017, [online], https://cks.nice.org.uk/menopause#!scenarioClarification:1 (accessed 27 January 2020)
  3. ACOG, ‘Endometrial hyperplasia’, American College of Obstetricians and Gynecologists, February 2012, [online], https://www.acog.org/Patients/FAQs/Endometrial-Hyperplasia?IsMobileSet=false (accessed 27 January 2020)
  4. FSRH, ‘Contraception for women aged over 40 years,’ Faculty of Sexual and Reproductive Health guideline, August 2017 (amended September 2019), [online], https://www.fsrh.org/standards-and-guidance/documents/fsrh-guidance-contraception-for-women-aged-over-40-years-2017/ (accessed 27 January 2020)
  5. NICE, ‘Contraception – IUS/IUD’, Clinical Knowledge Summary, National Institute for Health and Care Excellence, May 2019, [online] https://cks.nice.org.uk/contraception-iusiud#!scenario (accessed 27 January 2020)
  6. FSRH, ‘Intrauterine Contraception,’ Clinical Guidance, Clinical Effectiveness Unit, Faculty of Sexual and Reproductive Health, April 2015 (updated October 2015), [online], https://www.fsrh.org/standards-and-guidance/documents/ceuguidanceintrauterinecontraception/ (accessed 27 January 2020)
  7. Ibid
  8. Ibid