Let’s talk about Long Acting Reversible Contraceptives

Long Acting Reversible Contraceptives (LARCs)

Consultant Obstetrician and Gynaecologist at the Rotunda Hospital, Dr. Vicky O’Dwyer answers common questions related to contraceptives. In particular, in this section we will focus on questions on Long Acting Reversible Contraceptives.

Click on the highlighted text to watch Dr. O’Dwyer’s video response. Alternatively, you can find all the videos collated together here:


Long Acting Reversible Contraceptives are those methods of contraception that do not depend on you remembering to take or use them to be effective – this is why they are the most effective reversible methods.

LARCs do not have a long-term negative impact on fertility. You can have them removed and get pregnant within your next cycle. What can happen is your period can be a bit delayed. Contraception may also be masking an underlying condition like PCOS, where you do not ovulate. However, most people come off contraception, they get pregnant without any difficulties.

In this category:

The Copper Coil (IUCD)

The copper coil, also known as the IUCD, is a small T-shaped device covered in copper wire (coil). It is a non-hormonal form of contraception. A trained doctor inserts it into the uterus. It is the copper that repels sperm, preventing entry into the uterus. It also prevents a possible fertilised egg from embedding in the womb.

The copper coil is over 99% effective and you can also use it as a form of emergency contraception. It can last for 5-10 years before you need to have it removed or replaced.

The copper coil doesn’t interrupt sex and also works as soon as it’s inserted. It is beneficial to those that struggle to remember to take the pill daily. However it doesn’t protect against sexually transmitted infections (STIs) so it is always a good idea to use a condom as well!

Intrauterine System (IUS)

The IUS is a small T-shaped plastic device. A trained doctor inserts it into the womb.  It releases an artificial form of progesterone hormone, progestogen, which results in:

  • thinning of the uterine lining and therefore prevents a fertilised egg implanting.
  • It also stops the sperm from entering and reaching the egg.

The IUS is more than 99% effective and can also reduce the pain, the flow and the length of your periods. For this reason it may be inserted for the treatment of heavy periods. It doesn’t interrupt sex and it can stay in place until the menopause if inserted after the age of 45. In general, depending on the device, the IUS lasts for around 3-8 years.

It doesn’t protect against STIs and can also cause some spotting for around 6 months after insertion.

The insertion of a coil is not painless: Local anesthetics or general anesthesia can be used if you find the process to uncomfortable, so you should discuss your options with your nurse or doctor. If on the day of the insertion you find the process too uncomfortable, you can absolutely stop.

It’s very rare that it falls out. It may happen in someone who has very heavy periods.

The Implant/ The Bar

This is a small plastic bar placed under the skin of your bicep of the arm. You can feel it under the skin but you can’t see it. Only a trained doctor can perform the insertion and removal. It slowly releases progestogen, the artificial form of progesterone hormone, into the bloodstream. This results in:

  • no egg being released monthly (halt of ovulation).
  • thickening of the mucus at the neck of the uterus (the cervix). As a result, the sperm can’t swim through.
  • thinning of the uterus lining that prevents any possible fertilised egg implanting.

It lasts for up to 3 years before you need to have it removed/replaced. It is also over 99% effective. The implant has many benefits. It is breastfeeding-safe meaning you can breastfeed when you have it in. It also doesn’t interrupt sex and can reduce painful periods.

The implant doesn’t protect against STIs. Also, certain medications can affect its effectiveness.

The Injection

The injection contains artificial progesterone hormone, progestogen. The progestogen is slowly absorbed into the bloodstream from the muscle over 12 weeks and therefore must be retaken after the 12 weeks. It’s injected into your arm or your bum.

During the 12 weeks:

  • It stops ovulation
  • Thickens the lining of the womb, preventing implantation.

It is over 99% effective when used correctly. However it is only over 94% effective when used incorrectly.

This form of contraception doesn’t interrupt sex. However it doesn’t protect against STIs. It may also continue to cause some side effects for a few months after stopping the injections and can also take around 6-12 months for periods as well as fertility to return to normal after.

For more information, visit the dedicated page on the HSE website.


Doctor Vicky O'Dwyer, expert speaker for Debunking the myths: the science behind our sexual health the irish sexual health education outreach workshops for TY, 5th and 6th years.
Doctor Vicky O’Dwyer, expert speaker for Debunking the Myths: The Science Behind Our Sexual Health

Debunking the Myths – The Science Behind Our Sexual Health is a series of expert-led workshops and interactive tools for teenagers focused on sexual health. It is developed by the RCSI (Royal College of Surgeons in Ireland) Department of Obstetrics and Gynaecology in collaboration with the Rotunda Hospital to supplement the Relationship Sexuality Education (RSE) curriculum.

The aim of the project is to provide clear and factual information in relation to sexual health and stimulate open discussion and curiosity around the topic. For more information visit Debunking the Myths on Instagram or TikTok.