Hormone coils: all about coils, contraception and HRT

All about the Mirena coil and other types of hormone coils

What you need to know about the Mirena coil and other types of hormone coils 

Whether you are considering a hormone coil for contraception, to help manage heavy or painful periods, or – in the case of the Mirena coil – as part of your HRT regimen, this guide is for you. 

What is a hormone coil and how does it work? 

The hormone coil is a small, flexible T-shaped device inserted into your womb. All types of hormone coil contain progestogen, which is a synthetic form of the hormone progesterone. Progestogen is released steadily into your womb, which thickens the mucus from your cervix and makes it difficult for sperm to reach an egg. Progestogen also thins the lining of your womb so that it is less likely to accept a fertilised egg and may also stop the release of an egg (ovulation) for some women. 

What are the benefits of having a hormone coil fitted? 

Hormone coils are a very reliable contraceptive, lasting for up to eight years depending on the brand of coil you have fitted. It can also be used as a treatment for heavy and painful periods, and the Mirena coil can be used as the progesterone part of hormone replacement therapy (HRT). 

Mirena coil 

The Mirena coil is one of several hormone-containing coils. During perimenopause it has three potential uses 

1. As a contraceptive 

1. A treatment for heavy periods (it can reduce blood loss by more than 90% over six months for most women with heavy menstrual bleeding periods [1] 

1. The Mirena can be used with oestrogen and testosterone as part of HRT to protect the lining of the womb.  

If being used as part of HRT, the Mirena coil needs changing after five years. If being used solely for contraception, then it can be used for eight years. If solely for heavy periods, then it lasts for five years. 

Levosert and Benilexa  

Levosert and Benilexa are hormonal coils that also contain the hormone progestogen at the same dose as the Mirena coil, 52 mg of Levonorgestrel. Like the Mirena, they can be used as contraception, as a part of HRT or for heavy periods, the only difference being that if used for heavy periods then they have only been shown to be effective for up to three years rather than the five years seen with the Mirena. 

Kyleena coil 

Kyleena contains the hormone progestogen and is used for contraception alone. It is slightly smaller and lower dose than the Mirena and needs changing every five years. The smaller size means the Kyleena coil may be more suitable for women who have not previously been pregnant. 

Jaydess coil 

Like Kyleena, Jaydess is a smaller, lower dose coil so again may be more suitable for women who have not previously been pregnant. It is available for contraception and needs changing every three years. 

How is a coil is fitted? 

The coil is a simple procedure lasting up to 20 minutes. A local anaesthetic gel can be used to make you as comfortable as possible. 

A speculum, similar to that used when you have cervical screening, will be inserted into your vagina and the coil inserted through your cervix into your womb. Two fine threads attached to the bottom of the coil lie at the top of your vagina. These threads allow you and your health professional to check the coil is in place and mean it can be easily removed when needed. 

Does it hurt having a coil fitted? 

It is common that women will experience period-like discomfort during and after the fitting, so using a local anaesthetic gel during the procedure to help. You may experience some bleeding afterwards, and you can take over the counter painkillers for any period-like pain. 

Women using this type of coil can have HRT and testosterone, if needed. As the progestogen in these coils only works locally on the womb, many women find they have benefits from taking progesterone orally or as a pessary too. This is quite safe to do this.  

Watch Dr Louise Newson’s video on progesterone here.  

You can find out more about coil fitting at Newson Clinic here.

References

1. Creinin MD, Barnhart KT, Gawron LM, Eisenberg D, Mabey RG Jr, Jensen JT. Heavy Menstrual Bleeding Treatment With a Levonorgestrel 52-mg Intrauterine Device. Obstet Gynecol. 2023 May 1;141(5):971-978. doi: 10.1097/AOG.0000000000005137