An IUD is a small device placed in the womb that provides long-lasting contraception. Copper and hormonal versions work differently and affect periods differently, so the choice depends on what matters most to you.
The intrauterine device, still widely known as the coil, is one of the most reliable long acting contraceptive methods available, and also one of the most searched and most worried about. Women want to know whether insertion hurts, what a copper coil will do to their periods, how easily it comes out again and whether pregnancy is still possible with one in place.
This guide walks through the two types of IUD and how they differ, who they suit, exactly what happens during placement and removal, the side effects that are genuinely common, the complications that are rare, and the warning signs that mean you should contact your doctor rather than wait.
What Is an IUD and How Does It Prevent Pregnancy?
An intrauterine device is a small, flexible device, most often shaped like a T and roughly the size of a matchstick head across, which sits inside the cavity of the uterus. Two fine threads pass through the cervix into the top of the vagina so that the device can be checked and later removed. Once fitted, it works continuously for several years without anything for you to remember day to day.
There are two families of device, and they prevent pregnancy in different ways. The copper device releases a tiny amount of copper into the uterine cavity, which is hostile to sperm, impairs their movement and their ability to fertilise an egg, and alters the lining so that implantation is unlikely. It contains no hormones at all.
The hormonal device, often called an intrauterine system, releases a small dose of a progestogen directly into the uterus. This thickens cervical mucus so sperm cannot pass through easily, thins the lining of the uterus, and in some women partially suppresses ovulation. Because the hormone acts mainly locally, the amount circulating in the bloodstream is much lower than with tablets. Both types are very effective and neither depends on you remembering anything once fitted.
Hormonal IUD or Copper IUD: How the Two Compare
Choosing between the two is usually less about effectiveness and more about what you want your periods to do and whether you want hormones at all.
The copper device suits women who prefer to avoid hormones entirely, who have medical reasons to avoid progestogens, or who want the longest possible duration of use. Depending on the specific device, copper coils are licensed for around five to ten years. Their main drawback is bleeding: periods commonly become heavier, longer and more crampy, particularly in the first three to six months. Ovulation continues completely normally, so you keep your natural cycle and your usual premenstrual pattern. A copper device can also be fitted as emergency contraception within a few days of unprotected sex, and then simply left in place as ongoing contraception.
The hormonal device suits women who want lighter bleeding. It usually makes periods much lighter over time, and a proportion of users stop bleeding altogether, which is a recognised effect rather than a sign of anything being wrong. Because it thins the lining, it is also used to treat heavy periods, to relieve bleeding associated with fibroids or adenomyosis, and to protect the lining of the uterus in women taking oestrogen as part of hormone therapy. Its trade off is a period of unpredictable spotting while the lining adjusts, typically lasting three to six months, and hormone related effects such as breast tenderness, headaches, acne or mood changes in a minority of users.
Who Is a Good Candidate for an IUD?
Most women can use an intrauterine device, including women who have never been pregnant, teenagers, women who are breastfeeding, and women approaching the menopause. Having never given birth is not a reason to be refused a coil, although insertion can be a little more uncomfortable when the cervix has never dilated.
An IUD is particularly worth discussing if you struggle to take a pill consistently, if you want contraception you do not have to think about, if you cannot use oestrogen because of migraine with aura, high blood pressure or a history of blood clots, or if you want contraception that is fully reversible without any waiting period afterwards.
There are situations where a device is not fitted, or not fitted yet. These include a current or possible pregnancy, unexplained vaginal bleeding that has not yet been investigated, a current pelvic infection or untreated sexually transmitted infection, a cavity distorted by certain fibroids or by a congenital difference in the shape of the uterus, and known cancer of the cervix or lining of the uterus. A copper device is avoided in copper allergy and in Wilson disease, and a hormonal device is avoided in current breast cancer. Most of these are temporary obstacles rather than permanent ones. Your doctor will take a full history and perform a gynaecological examination before recommending a device.
IUD Placement: What Actually Happens, Step by Step
Knowing the sequence in advance makes the appointment far less daunting, because almost every part of it is brief.
First, pregnancy is excluded and your history is reviewed. Depending on your circumstances you may be offered screening for infection, since fitting a device in the presence of an untreated infection is what carries risk. You then lie on the examination couch as you would for a smear test. A speculum is placed, the cervix is cleaned with antiseptic, and your doctor performs a brief internal examination to establish the position and angle of the uterus.
A thin instrument is used to steady the cervix, and a fine sound is passed to measure the depth of the cavity so that the device sits at the correct height. The IUD, loaded into a slim insertion tube, is then passed through the cervical canal and released at the top of the cavity, where its arms open out. The tube is withdrawn and the threads are trimmed so that a couple of centimetres sit in the vagina. From speculum in to speculum out, the process usually takes around five to ten minutes, and the device itself is placed in well under a minute.
Does It Hurt, and How Is the Discomfort Managed?
Honesty helps more than reassurance here. Most women feel strong period like cramping at two moments: when the cervix is steadied and when the device passes through it. For some the discomfort is mild and brief. For others it is sharp and genuinely painful, and there is no reliable way to predict in advance which you will be. The cramping usually eases within minutes of the speculum being removed, though a dull ache and some bleeding can continue for a day or two.
You do not have to simply endure it. Taking a simple anti inflammatory painkiller an hour beforehand is commonly advised. Local anaesthetic applied to or injected around the cervix, a cervical block, and in selected cases sedation or a short general anaesthetic are all legitimate options to discuss beforehand rather than during the procedure. Feeling faint immediately afterwards is not unusual; it settles with a few minutes lying flat. Ask what pain relief is available when you book, and say clearly during the appointment if you want it stopped.
When Can an IUD Be Fitted?
A device can be fitted at any point in the cycle provided pregnancy can reasonably be excluded, though many doctors prefer the days during or just after a period, when the cervical canal is slightly more open and pregnancy is unlikely. After a vaginal or caesarean birth, a coil can be inserted within the first forty eight hours or, more commonly, from about four weeks onwards once the uterus has returned to its normal size. Following a miscarriage or termination in the first or second trimester, a device can usually be fitted immediately or at the follow up visit, as long as there is no infection. Fitting straight away avoids the gap during which an unplanned pregnancy can occur, since ovulation can return within a few weeks.
The First Few Months After Insertion
The uterus needs time to accommodate a foreign object, and the first three to six months are the adjustment period for both types of device. Cramping that comes and goes, particularly in the first few days and around the time you would expect a period, is normal and responds to simple painkillers and a heat pack. Irregular spotting or light bleeding between periods is extremely common early on and is not a sign that the device is failing. Some women notice a change in the amount of everyday vaginal discharge, which usually settles.
What is not part of normal settling in is fever, foul smelling discharge, pain that is escalating rather than easing, or pain during sex that is new and persistent. Those need to be assessed rather than waited out, because the small risk of infection is concentrated in the first three weeks after insertion.
Checking the Threads
You can check the device yourself. Wash your hands, sit or squat, and insert a finger into the vagina until you feel the cervix, which has the texture of the tip of your nose. The threads should be felt as two fine strands emerging from it. Many doctors suggest checking after each period for the first few months, then occasionally. Never pull on the threads. If you cannot feel them, if they feel much longer or shorter than before, or if you feel hard plastic at the cervix, use condoms and arrange a check.
Copper IUD Side Effects
The copper device has no systemic hormonal effects, so its side effects are concentrated in the uterus itself. The most consistent one is a change in bleeding. Periods often become heavier, sometimes lasting a day or two longer, and cramping tends to be more noticeable, especially on the heaviest days. This is most pronounced in the first three to six months and improves for many women after that, though for some it persists.
Heavier bleeding is worth taking seriously rather than tolerating indefinitely, because sustained heavy periods can lower your iron stores and leave you tired and short of breath. If your bleeding is heavy enough to soak through protection hourly, to pass large clots or to make you plan your life around it, that is a reason to be reviewed. Iron levels can be checked, anti inflammatory medication taken during the heaviest days can reduce both bleeding and cramping, and switching to a hormonal device is always an option.
Spotting between periods can occur in the early months. Some women also report an increase in ordinary discharge. What the copper device does not do is alter your hormones, so it does not cause hormonal weight gain, mood changes or reduced libido; if you notice those, look elsewhere for the cause. Persistent pelvic pain is never simply attributed to the device without an examination and a scan to confirm it is correctly positioned.
How a Hormonal IUD Affects Your Periods
The hormonal device works largely by thinning the lining of the uterus, and your bleeding pattern follows that directly. Expect the first months to be untidy: frequent light spotting, prolonged small amounts of brown discharge, and unpredictable timing are all typical while the lining thins. This phase commonly lasts three to six months and is the single most common reason women consider having the device removed early, which is why knowing about it in advance matters.
Once the lining has settled, periods usually become markedly lighter and shorter, and cramping generally eases. A significant proportion of users find their periods stop altogether after the first year. This is not a build up of blood inside you and it does not affect your future fertility; there is simply very little lining to shed. It is a recognised and harmless effect, and periods return once the device is removed.
Because bleeding becomes so light, some women worry about knowing whether they are pregnant. If you have no bleeding at all with a correctly placed hormonal device, that is expected. Take a pregnancy test only if you develop symptoms of pregnancy, if you cannot feel the threads, or if you had previously been bleeding regularly and something else has changed. If your bleeding becomes heavy again after a long quiet period, or you start bleeding after sex, that warrants a review to look for a separate cause of irregular bleeding.
IUD Removal and How Quickly Fertility Returns
Removal is considerably quicker and easier than insertion, and this surprises most women. A speculum is placed, the threads are grasped with a fine pair of forceps, and steady gentle traction is applied. The arms of the device fold upwards as it passes through the cervix and it slides out. The whole thing takes seconds. Most women feel one short, sharp cramp and then it is over, with mild cramping and light bleeding for a day.
A device is removed when it reaches the end of its licensed duration, when you want to conceive, when side effects are not acceptable to you, or when you no longer need contraception. If you are having it removed but do not want to become pregnant, either arrange a replacement at the same appointment or avoid unprotected sex in the week beforehand, because sperm can survive several days and fertility resumes immediately. If the threads cannot be seen, an ultrasound locates the device and removal is then usually carried out with a fine camera through the cervix under local anaesthetic.
Fertility returns essentially at once, with both types. There is no clearing out period and no need to wait a few cycles first. Ovulation typically resumes in the very first cycle after removal, and with a copper device it was never interrupted at all, so conception in that first month is entirely possible. If you are planning pregnancy, start folic acid before the removal appointment and begin tracking your ovulation signs straight away.
Can You Get Pregnant With an IUD in Place?
Yes, although it is uncommon. Both types of device are among the most reliable reversible methods, but no method is absolute, and a small number of pregnancies do occur each year among users. Most of these happen because the device has moved down or been expelled without the woman realising, which is one of the practical reasons for learning to check your threads.
Suspect pregnancy if you miss a period when you normally bleed regularly, if you develop nausea, breast tenderness or unusual fatigue, or if you cannot locate the threads. Take a standard urine pregnancy test; it works normally with a device in place.
If the test is positive, arrange to be seen promptly rather than at your convenience. The first priority is a scan to confirm that the pregnancy is inside the uterus. A device does not cause ectopic pregnancy, but because it is so good at preventing normal intrauterine pregnancy, a higher share of the pregnancies that do occur turn out to be outside the uterus. Severe one sided pain, shoulder tip pain or faintness alongside a positive test is an emergency.
If the pregnancy is in the uterus and you wish to continue it, current practice is generally to remove the device early if the threads are visible, because leaving it in place is associated with a greater chance of miscarriage, infection and early labour. If the threads cannot be seen, removal may not be possible and the pregnancy is then monitored more closely. These decisions are individual and are made with you, not for you.
Rare Complications and Persistent Myths
Two complications are worth understanding calmly. Expulsion means the device partially or completely slips out of the uterus. It happens to a small minority of users, most often in the first three months, and is more likely after childbirth, with very heavy periods and with strong cramping. It is usually painless and may be noticed only as absent threads, longer threads, or the device itself in a sanitary pad or the toilet. A replacement can be fitted once things have settled.
Perforation, where the device passes partly or fully through the wall of the uterus during insertion, is genuinely rare, occurring in around one or two of every thousand insertions, and is more likely when the uterus is soft, such as shortly after birth or while breastfeeding. It usually presents as severe pain during or after fitting, or later as absent threads with a positive scan finding. A perforated device is retrieved with keyhole surgery.
Several persistent beliefs are simply untrue. A coil does not cause infertility; fertility returns to your own baseline on removal. It cannot travel around your body or reach your heart. It does not stop you using tampons, although menstrual cups should be released from suction carefully before removal. Your partner may occasionally feel the threads, but this is usually solved by trimming them. Finally, a device is not an abortion method; it works mainly by preventing fertilisation in the first place.
When to Contact a Doctor
A routine check is usually arranged around four to six weeks after fitting to confirm the device is correctly positioned and the threads are the right length. Between appointments, contact your doctor rather than waiting if you notice any of the following.
- Fever, chills, or discharge that smells offensive, particularly in the first few weeks after insertion
- Severe or worsening lower abdominal pain, rather than cramping that is gradually settling
- A positive pregnancy test, and urgently if this comes with one sided pain, faintness or shoulder tip pain
- Threads you can no longer feel, threads that feel much longer or shorter, or hard plastic at the cervix
- Bleeding heavy enough to soak through protection every hour, or bleeding that starts again after months of none
- New pain during sex, or pain reported by your partner that does not resolve after the threads are trimmed
An IUD is designed to be a method you can largely forget about, and for most women that is exactly how it works out. Knowing which symptoms belong to the normal settling in period and which do not is what makes the difference between an anxious first year and a straightforward one.
References
This article was prepared with reference to the following independent health sources.
- NHS. IUD (copper coil)
- NHS. IUS (hormonal coil)
