Hormonal coil (LNG-IUD or IUS)

The hormonal coil is a small T shaped plastic device that is fitted in your womb.

Hormonal coil (LNG-IUD or IUS): an overview

The hormonal coil (LNG-IUD or IUS) is a small, T-shaped plastic device that is fitted in your womb, where it releases a small amount of progestogen hormone.

A hormonal coil is long-acting and reversible, so you can take it out if you want to get pregnant.

The most known brand of hormonal coil is Mirena coil. However, there are different brands, sizes and doses of hormone available, and they last different lengths of time.

You can book an appointment for contraception at axess here.

Lasts for
3 to 8 years
Bleed cycle

Frequently Asked Questions

How long does it last?

Hormonal coils are effective to prevent pregnancy for between three to eight years, depending on the brand.

You can discuss with your clinician or GP which hormonal coil may be best suited to you.

The most common brand, Mirena, has been extended to last for eight years by the manufacturer. If you already have a Mirena coil fitted and were told to have it replaced for contraception after five or six years, you can be assured that your coil is now effective for up to eight years.

After eight years, it should be removed or replaced, unless you were 45 years old when it was fitted. In this case, it can stay fitted until age 55, or until no longer needed.

Some hormonal coils can also be used as part of Hormone Replacement Theory (HRT). In this instance, the coil must be replaced every five years.

How will it affect my bleeding pattern?

The hormonal coil is likely to affect your normal periods.

It is common to have irregular bleeding and spotting for the first six months after fitting. After six months, most people have light monthly bleeds. Many have no bleeding of very minimal amounts.

How effective is a hormonal coil?

A coil is one of the most effective methods of contraception.

It is a Long Acting Reversible Contraception (LARC) which are usually more reliable, as the user needs to do very little for it to remain effective (rather than, for example, remembering to take tablets).

A hormonal coil is over 99% effective, which means approximately less than one in 100 people will get pregnant in the first year of use (with perfect and typical use).

What are the advantages of a hormonal coil?

The advantages of a hormonal coil include:

  • It works either as soon as it is put in, or after seven days, depending on what contraception you were using before fitting
  • To prevent pregnancy, it works between three or eight years, depending on type. It may be left up to ten years if you had it fitted at age 45 years or older
  • If you have heavy or painful periods, the hormonal coil can make your bleeds lighter and shorter. They may even stop completely or be minimal
  • You do not have to prepare for, or interrupt, sex
  • You do not have to remember something every day or every month
  • It can be used if you're breastfeeding
  • It's not affected by other medicines
  • Your fertility returns to normal when the hormonal coil is taken out
  • Side effects are rare
What are the disadvantages of a hormonal coil?

The disadvantages of a hormonal coil include:

  • You'll need an internal examination to fit the hormonal coil and you are encouraged to feel for the threads for yourself, monthly
  • The hormonal coil does not protect you from sexually transmitted infections, so you may need to use condoms as well
  • The hormonal coil does not increase your risk of infection, but if you get an infection when a copper coil is in place, it could lead to a pelvic infection if not treated
Is the hormonal coil suitable for me?

Most women can use a hormonal coil, but you will be asked about your family and medical history to determine if it is the best method for you.

It is a good alternative for women who can't take, or do not want to take, the hormone oestrogen (which is in the combined pill, patch and vaginal ring).

It may not be suitable for women with some medical conditions, including:

  • Pelvic infection
  • Unexplained vaginal bleeding
  • Some fibroids or abnormalities of the womb
  • Cancer of the cervix or lining of the womb
  • Breast cancer (in the past five years)
  • Liver disease
  • Heart disease
  • An untreated STI

It may be helpful for treatment of:

  • Heavy periods
  • Endometriosis
When can it be fitted?

If there is no pregnancy risk, a hormonal coil can be fitted at any time in your cycle.

If you have had sex without a condom, and you are not on any other contraception, you will have to wait for three weeks after the sex before a hormonal coil can be fitted.

A hormonal coil cannot be fitted as emergency contraception.

When will it be effective?

A hormonal coil may work straight away after fitting, in the first five days of your cycle, or if you have been on another hormonal contraception.

Any other time, it may be seven days before it works and you will need to use additional contraception.

You will be advised of this by the practitioner who fits your coil.

What are the side effects of a hormonal coil?

In addition to the side effects for all coils, it is common to have irregular bleeding and spotting for the first six months with a hormonal coil.

Short time side effects also include breast tenderness, acne and headaches, which are all rare and usually go away.

Long term rare side effects may include:

  • Minor changes in mood or reduced sex drive
  • Irregular vaginal bleeding and pain
  • Small cysts which develop on ovaries, that disappear without treatment
Can I use a hormonal coil if I am approaching menopause?

If you are 45 years old (or older) when a hormonal coil is fitted, you can keep the same one until you no longer need contraception, or reach menopause, or you are 55 years old. It can also be used as hormone replacement therapy (HRT) and lasts for five years.

Will a hormonal coil affect my future fertility?

Your fertility will return to normal when the hormonal coil is removed.

If you decide to have your hormonal coil removed, but do not want to get pregnant, you must either have no sex or use condoms for 7 days before removal as sperm can live up to 7 days in your body.