Coil Types Contraception: Your Expert Guide to IUDs and IUS

Table of Contents

• What is a Coil? Understanding IUDs and IUS
• Copper Coil vs. Hormonal Coil: Key Differences
• How Coil Types Contraception Works
• Benefits and Advantages of Coil Contraception
• Getting a Coil Fitted: The Procedure & Aftercare
• Potential Side Effects and Risks
• Frequently Asked Questions (FAQ)

Navigating the world of long-acting reversible contraception (LARC) can be empowering. Among the most effective options are intrauterine devices, commonly known as "coils." Understanding the different coil types contraception available is the first step toward making an informed choice about your reproductive health. This comprehensive guide will demystify the copper IUD and hormonal IUS, explaining how they work, their pros and cons, what to expect during fitting and removal, and how to decide which might be right for your body and lifestyle. Whether you're seeking a hormone-free option or highly effective period control, this guide covers everything you need to know.

What is a Coil? Understanding IUDs and IUS

The term "coil" is a colloquial name for a small, T-shaped device that is inserted into the uterus to prevent pregnancy. It's a form of Long-Acting Reversible Contraception (LARC), meaning it provides protection for several years but can be removed at any time by a healthcare professional, with fertility typically returning quickly. There are two main coil types contraception:

• Copper IUD (Intrauterine Device): A non-hormonal coil wrapped in a small amount of copper. It's a purely physical and chemical method of contraception.
• Hormonal IUS (Intrauterine System): A device that contains and slowly releases the progestogen hormone levonorgestrel. Popular brand names include Mirena, Benilexa, Levosert, and Kyleena.

Both are over 99% effective at preventing pregnancy, making them more reliable than the pill, patch, or ring. Their effectiveness stems from the fact that, once fitted, they require no daily or monthly action from the user.

"The shift towards LARC methods like coils represents a significant advancement in contraceptive autonomy. They offer 'set-and-forget' reliability, which is ideal for individuals who want highly effective birth control without the burden of daily routine." – Illustrative Expert Opinion

Copper Coil vs. Hormonal Coil: Key Differences

Choosing between a copper and hormonal coil depends on your body, your menstrual cycle preferences, and your medical history. Here’s a detailed comparison to help you understand the core distinctions.

Feature	Copper IUD (Non-Hormonal)	Hormonal IUS (e.g., Mirena, Benilexa)
Primary Mechanism	Copper ions create an inflammatory reaction toxic to sperm and eggs, preventing fertilisation.	Progestogen thickens cervical mucus (blocking sperm) and thins the uterine lining. May also suppress ovulation in some users.
Hormones	None. A hormone-free option.	Contains levonorgestrel (a progestogen).
Effect on Periods	Often makes periods heavier, longer, or more painful, especially in the first 3-6 months.	Usually makes periods lighter, shorter, and less painful. Many users experience very light or no periods after a year.
Duration	Can last 5 to 10 years, depending on the brand and type.	Lasts 3 to 8 years (e.g., Kyleena: 5 years, Mirena: up to 8 years for contraception).
Ideal For	Those who cannot or prefer not to use hormones; those who want immediate, long-term protection; after emergency contraception.	Those with heavy or painful periods (it's often prescribed for this); those seeking to reduce or eliminate menstrual bleeding.

Common Hormonal IUS Brand Names

In the UK and Europe, you might encounter several brands of hormonal IUS. While they all work on the same principle, they differ in hormone dose and licensed duration:

• Mirena: The most well-known, licensed for 8 years of contraception and for treating heavy periods.
• Benilexa & Levosert: Similar to Mirena, typically licensed for 5-6 years.
• Kyleena: A smaller device with a lower hormone dose, licensed for 5 years.
• Jaydess: The smallest IUS with the lowest dose, licensed for 3 years.

How Coil Types Contraception Works

The mechanism of action varies significantly between the two main coil types contraception, which explains their different effects on your cycle.

How the Copper IUD Works

The copper IUD is a spermicidal device. The copper wire coiled around the device releases copper ions into the uterine fluid. This creates a local inflammatory reaction that is toxic to sperm, impairing their motility and ability to fertilise an egg. Research, such as that referenced in imaging studies of IUDs, supports the understanding of their placement and local effect (Peri, 2007). Essentially, it creates an environment where sperm cannot survive or function normally. It may also prevent a fertilised egg from implanting, though its primary action is to prevent fertilisation.

How the Hormonal IUS Works

The hormonal IUS works primarily in three ways:

1. Thickens Cervical Mucus: The steady release of progestogen causes the mucus at the entrance to the uterus (the cervix) to become thick and sticky. This forms a near-impenetrable barrier, preventing sperm from entering the uterus.
2. Thins the Uterine Lining (Endometrium): The hormone suppresses the growth of the lining of the womb. This makes it unsuitable for the implantation of a fertilised egg. A thin lining also results in much lighter or absent menstrual bleeding.
3. May Suppress Ovulation: In some individuals, particularly with higher-dose IUS like Mirena, ovulation may be partially or fully suppressed. However, this is not its primary mechanism for all users.

Benefits and Advantages of Coil Contraception

Why choose a coil? The benefits extend far beyond just preventing pregnancy.

• "Fit and Forget" Convenience: Once inserted, you don't need to think about contraception daily, weekly, or monthly. There's no routine to remember.
• Cost-Effective in the Long Run: While the upfront cost of the device and fitting can be higher, when spread over its 3-10 year lifespan, it becomes very economical. In many countries, it's free through national health services.
• Rapid Return to Fertility: Unlike some contraceptive methods that can cause a delay, fertility typically returns to normal almost immediately after removal.
• Discreet and Partner-Independent: It's entirely under your control. Your partner won't know it's there unless you tell them.
• Non-Interference with Sex: It doesn't interrupt spontaneity. For added pleasure and intimacy, consider exploring complementary products like sensual massage oils and accessories.
• Additional Medical Benefits (IUS): The hormonal IUS is licensed to treat heavy menstrual bleeding (menorrhagia) and can provide relief from painful periods. It can also be used as part of Hormone Replacement Therapy (HRT).

"The high efficacy and long duration of coils address two major concerns with user-dependent methods: human error and access. They provide continuous protection, which is crucial for empowering individuals to plan their futures with confidence." – Illustrative Expert Opinion

Getting a Coil Fitted: The Procedure & Aftercare

Understanding the fitting process can help alleviate anxiety. The procedure is usually done by a trained doctor or nurse at a sexual health (GUM) clinic, your GP surgery, or some contraception clinics.

Before the Appointment

You'll typically have a consultation to discuss your medical history, choose the right coil, and rule out pregnancy or any infections (like STIs). Fitting is often recommended during or just after your period, as the cervix is slightly softer and pregnancy is very unlikely.

The Fitting Procedure

The fitting itself usually takes about 5-10 minutes, though the entire appointment may last 20-30 minutes.

1. You'll lie on an examination bed, similar to a smear test.
2. The clinician will insert a speculum to see your cervix.
3. They may apply a local anaesthetic to your cervix to reduce discomfort.
4. The uterus is measured to ensure correct device size.
5. The coil is inserted through the cervix and into the uterus using a narrow inserter tube. You might feel a period-like cramp or sharp sensation for a minute.
6. The threads are trimmed, leaving about 2-3cm inside the vagina to allow for future checks.

Some cramping and light bleeding for a few days after is normal. Over-the-counter pain relief can help.

Checking and Removal

You may be advised to check for the threads monthly after your period. Removal is a quicker and often simpler procedure done by a clinician, involving gentle pulling on the threads. A new coil can be inserted during the same appointment if desired.

Potential Side Effects and Risks

While highly safe for most people, it's important to be aware of potential side effects and risks.

Common Side Effects

• For Copper IUD: Heavier, longer, or more painful periods, especially for the first 3-6 months. Spotting between periods.
• For Hormonal IUS: Irregular bleeding or spotting for the first 3-6 months. Headaches, breast tenderness, mood changes, or acne (similar to other progestogen-only methods). Periods usually become much lighter or stop.
• For Both: Cramping or backache for a few days after insertion.

Uncommon but Serious Risks

• Expulsion: The coil can partially or completely fall out of the uterus, most commonly in the first few months. You may not notice it, which is why checking threads is important.
• Perforation: Very rarely (less than 1 in 1000 fittings), the device can make a small hole in the wall of the uterus during insertion. This usually requires surgical removal.
• Infection: There's a small risk of pelvic infection in the first few weeks after insertion if bacteria are introduced. Screening for STIs beforehand minimises this risk.
• Ectopic Pregnancy: If a pregnancy occurs with a coil in place (very rare), there is a higher chance it will be ectopic (outside the womb), which is a medical emergency.

Important: Seek immediate medical advice if you experience severe abdominal pain, very heavy bleeding, fever with chills, or if you can feel the coil itself at your cervix.

Frequently Asked Questions (FAQ)

Does getting a coil fitted hurt?

Experiences vary widely. Most people feel some period-like cramping during the insertion, which can range from mild to moderately painful but is usually brief. Taking pain relief like ibuprofen an hour before your appointment can help. Some clinics offer local anaesthetic to the cervix. Cramping may continue for a few hours or days after.

Can I use a coil if I've never had children?

Can a coil make you gain weight?

References

• Peri N (2007). Imaging of intrauterine contraceptive devices.. PubMed:17901142
• Weisberg E (1980). Fitting of diaphragms.. PubMed:7432308
• Tagg PI (1995). The diaphragm: barrier contraception has a new social role.. PubMed:8610032

Last updated March 27, 2026