What Is a LARC? Birth Control That Lasts Years

LARC stands for long-acting reversible contraception, a category of birth control that works for years after a single placement and can be removed whenever you want your fertility back. The group includes intrauterine devices (IUDs) and the subdermal contraceptive implant.¹ What makes these methods stand apart from pills, patches, and rings is that they do not depend on you remembering to do something every day or every month, which translates into dramatically lower real-world failure rates.

The Three Types

There are currently three LARC devices available in most countries, and each works through a different mechanism.

Copper IUD: A small T-shaped plastic frame wrapped in copper wire, placed inside the uterus. It contains no hormones. The copper releases ions that create a local inflammatory response toxic to sperm, preventing fertilization.² It is FDA-approved for up to 10 years.
Hormonal IUD: A similar T-shaped frame that releases the progestin levonorgestrel directly into the uterus. This thins the uterine lining, thickens cervical mucus so sperm have difficulty getting through, and in most users does not shut down ovulation entirely.³ Several sizes exist with varying hormone doses and approved durations ranging from three to eight years, depending on the product.
Subdermal implant: A single thin, flexible rod about the size of a matchstick that a clinician inserts just under the skin of your upper arm. It steadily releases the progestin etonogestrel, which primarily works by suppressing ovulation. It is approved for three years of use.

All three are classified as “reversible” because, unlike sterilization, they can be taken out at any point and fertility returns quickly.

How Hormonal Versus Copper IUDs Differ in Mechanism

The copper IUD is the only highly effective hormone-free LARC option. Because it relies purely on a local chemical reaction, it does not cause the hormonal side effects some people experience with progestin-containing methods. It works immediately upon insertion, which is part of why it doubles as emergency contraception (more on that below).

The hormonal IUD delivers levonorgestrel directly to the uterine tissue, where local concentrations become hundreds of times higher than what you would get from a daily pill, while bloodstream levels stay comparatively low.³ No single mechanism accounts for its effectiveness on its own; the combination of a thinned endometrium, thickened cervical mucus, and changes to tubal motility together make pregnancy extremely unlikely.⁴ Because most of the hormonal action is local rather than systemic, many people who have had trouble tolerating oral contraceptives find the hormonal IUD easier to live with.

Real-World Effectiveness

The gap between LARC methods and shorter-acting options is not subtle. A large prospective study published in the New England Journal of Medicine followed thousands of participants and found that those using pills, the patch, or the ring had a failure rate of about 4.55 unintended pregnancies per 100 person-years, compared with just 0.27 per 100 person-years among LARC users.⁵ That means the short-acting methods failed at roughly 20 times the rate. The reason is not that the pill is an inherently bad contraceptive when taken perfectly. The reason is that perfection is hard. Missed doses, late pharmacy refills, and inconsistent timing all add up. LARC methods sidestep that entire problem because they sit in place and work continuously with no user input.

Higher effectiveness and higher continuation rates are consistently associated with LARC use across multiple study populations.⁶

How Long They Actually Last

The FDA-approved durations are conservative estimates. Research has shown that several LARC methods remain effective well beyond their labeled lifespans. A systematic review found that the 52-milligram hormonal IUD maintained extremely low pregnancy rates in years six and seven, with a pooled rate of roughly 0.02 pregnancies per 100 person-years during those extended years.⁷ The copper IUD showed zero pregnancies per 100 person-years in a pooled analysis of years 11 and 12.⁷

For the implant, studies indicate it continues to suppress ovulation adequately for at least a fourth year, with serum etonogestrel levels remaining above the threshold needed to prevent ovulation across all body mass index categories.⁸ Earlier data confirmed this pattern for at least one year past the approved three-year window.⁹ This matters because it means if you are a few months or even a year late for a replacement appointment, you are not suddenly unprotected. Still, most clinicians recommend following the labeled timeframe unless you and your provider have specifically discussed extended use.

What Insertion Feels Like and How to Manage Pain

Insertion anxiety is one of the biggest reasons people hesitate to try a LARC, especially an IUD. The implant insertion is simpler: a clinician numbs a small area on your inner upper arm, uses a preloaded applicator to slide the rod under the skin, and the whole thing typically takes less than a minute. Most people feel pressure and maybe a pinch.

IUD insertion is more involved. It requires a speculum, a device to stabilize the cervix, measurement of the uterus, and then placement of the IUD itself. Without pain management, many people describe it as a sharp cramp that peaks for a few seconds. Research shows that a paracervical block, which is a numbing injection around the cervix, meaningfully reduces that pain. In a randomized trial among people who had never given birth, those who received a paracervical block reported median pain scores about 40 percent lower than those who received no block.¹⁰ A more recent triple-arm trial confirmed this: participants receiving lidocaine paracervical blocks reported lower pain at every stage of IUD insertion, along with higher satisfaction, compared with placebo groups.¹¹

If your provider does not routinely offer a nerve block for IUD placement, you can ask. Pain management practices vary widely between clinics, and requesting it is reasonable. Some clinics also offer sedation or use cervical-softening medications beforehand, though the evidence for cervical priming is more mixed.

Bleeding Patterns and Side Effects

The side-effect profile depends heavily on which LARC you choose, and bleeding changes are the most noticeable difference.

The copper IUD tends to make periods heavier and crampier, especially in the first few months. Over time, bleeding patterns usually stabilize but remain somewhat heavier than your pre-IUD baseline.¹² This is the most common reason people have the copper IUD removed early.

The hormonal IUD pushes bleeding in the opposite direction. Many users experience lighter periods, and a meaningful fraction stop bleeding altogether. A meta-analysis found that very few users had no periods at all in the first three months, but by the end of the first year, about one in five had at least one stretch of amenorrhea.¹³ Irregular spotting is common in the early months and tends to settle down.

The implant’s bleeding pattern is less predictable. Some people get lighter or absent periods; others develop prolonged or irregular spotting that can last weeks. This unpredictability is one of the primary reasons for early implant removal.¹⁴ There is currently no reliable way to predict in advance how your body will respond.

Fertility After Removal

One persistent myth about IUDs and implants is that they impair future fertility. They do not. One older but often-cited study found that among people who had an IUD removed specifically to get pregnant, about 94 percent conceived, and the majority of those conceptions happened in the first three months after removal.¹⁵ A broader systematic review looking at all reversible contraceptive methods found that roughly 83 percent of former users were pregnant within 12 months of stopping, and the rate was not significantly different between hormonal method users and IUD users.¹⁶ For implant users specifically, pregnancy rates in the first year after removal range from 76 to 100 percent and are comparable to rates after stopping any other reversible method.¹⁷

This rapid return to fertility is different from what some people experience after stopping injectable contraception, where delays of several months are well documented. It is one of the reasons “reversible” is emphasized in the LARC acronym. Unlike sterilization, nothing permanent happens to your reproductive anatomy while a LARC is in place.

Non-Contraceptive Benefits of the Hormonal IUD

The hormonal IUD has accumulated a long list of recognized therapeutic uses beyond pregnancy prevention. Because it dramatically reduces the buildup of uterine lining, it is an effective treatment for heavy menstrual bleeding from a variety of causes, including fibroids and adenomyosis. It also reduces menstrual pain and can help prevent iron-deficiency anemia that results from chronic heavy periods.¹⁸ It is used to manage endometrial hyperplasia, which is an overgrowth of the uterine lining that can become precancerous, and it alleviates pain from endometriosis.¹⁹

For people who are prescribed tamoxifen for breast cancer, the hormonal IUD reduces the risk of endometrial polyps that tamoxifen can provoke.¹⁹ In many cases, clinicians prescribe the hormonal IUD primarily for these therapeutic reasons, with contraception as a secondary benefit.

Teens and People Who Have Never Given Birth

For years, a widespread belief held that IUDs were only appropriate for people who had already been pregnant. That idea is outdated. The American College of Obstetricians and Gynecologists recommends IUDs and implants as first-line options for teenagers.²⁰ Research has found that while younger adolescents do have a somewhat higher rate of IUD expulsion (where the device partially or fully comes out on its own), the difference is not large enough to outweigh the benefits. In most situations, the advantages of IUD use clearly outweigh the risks regardless of age or whether someone has given birth.²⁰

Insertion can be slightly more uncomfortable if you have never been pregnant, since the cervical canal has never been dilated. This is where the pain management strategies mentioned earlier become especially relevant.

Placement Right After Pregnancy or Abortion

Timing LARC placement to happen immediately after a delivery or abortion has clear practical advantages: you are already in a clinical setting, motivation is high, and there is no gap in coverage during which an unintended pregnancy could occur. A trial published in the New England Journal of Medicine found that people who received an IUD immediately after a uterine aspiration procedure had a 92 percent IUD use rate at six months, compared to about 77 percent in the group told to come back later for placement.²¹ Five pregnancies occurred in the delayed group, all in people who never returned for the IUD; none occurred in the immediate group.

The trade-off is a modestly higher risk of the IUD being expelled, since the uterus is still returning to its pre-pregnancy size. A Cochrane review confirmed that immediate post-abortion IUD insertion is safe and practical, but expulsion rates are higher than with delayed placement. The review concluded that overall, more people end up protected at six months with immediate placement because many who are told to return simply do not come back.²²

The Copper IUD as Emergency Contraception

A lesser-known use of the copper IUD is as emergency contraception. When inserted within five days of unprotected sex, it reduces the chance of pregnancy by over 99 percent, making it significantly more effective than emergency contraceptive pills.²³ Despite this, very few providers mention it when someone comes in asking for emergency contraception. The copper IUD has the added benefit of then staying in place as ongoing contraception for up to a decade, unlike a one-time pill.

The main barrier is access. Getting an IUD inserted requires an appointment with a trained provider, which is harder to arrange on short notice than picking up a pill at a pharmacy. But if you can get the appointment, the copper IUD is the most effective emergency option available.

Why People Stop Early

Even though LARCs have high continuation rates compared to other methods, early removal does happen. In a large U.S. prospective study, about 7 to 8 percent of hormonal IUD and copper IUD users and about 7 percent of implant users discontinued within the first six months. The leading reason for IUD removal was cramping, while for implant users, it was irregular or frequent bleeding.¹⁴ Younger age alone was not associated with higher early discontinuation in that study.

Qualitative research reveals that the experience of requesting removal can itself be a barrier. Some people have described feeling dismissed by providers when asking to have their IUD taken out, being told to “just leave it” and wait for side effects to resolve.²⁴ This is a recognized problem in the field, and patient advocates have pushed back against the idea that providers should discourage removal. A method is only truly “reversible” if the person using it can have it removed promptly when they want to, for whatever reason.

Access Barriers Around the World

LARC methods exist and are highly effective, but that effectiveness only matters if people can actually get them. The upfront cost of an IUD or implant is higher than a month’s supply of pills, which creates a barrier even though LARC is far cheaper over time. In many public health systems, the devices themselves may not be stocked at local clinics, and trained providers may not be available. A study of Brazilian women found that the primary reasons for seeking LARC at a hospital-level clinic were that the methods were not available at local primary care facilities, the cost was prohibitive elsewhere, and trained providers were concentrated in urban centers.²⁵ A systematic review from Ethiopia identified similar structural problems alongside social ones: partner disapproval, religious prohibitions, and influence from community leaders all reduced LARC uptake, while open partner communication and supportive counseling during prenatal visits improved it.²⁶

In the United States, the Affordable Care Act required most insurance plans to cover all FDA-approved contraceptive methods with no out-of-pocket cost, which significantly improved access. However, coverage gaps, network restrictions, and variability in Medicaid programs mean that barriers persist for many people, particularly those who are uninsured or underinsured.

The Dalkon Shield and Why IUD Reputation Took Decades to Recover

If you have ever heard an older family member say something vaguely alarming about IUDs, the Dalkon Shield is probably why. This poorly designed IUD was sold in the 1970s and caused serious pelvic infections, infertility, and some deaths, largely because of a multifilament tail string that wicked bacteria into the uterus. The resulting lawsuits, media coverage, and regulatory fallout drove IUD use in the United States to near zero for more than a decade. Modern IUDs bear essentially no design resemblance to the Dalkon Shield and use monofilament strings, but the reputational damage lingered. Researchers have traced the recent resurgence in IUD use to a combination of the passage of time, new product development, and a shift in provider attitudes that only took hold in the early 2000s.²⁷

Understanding this history is useful because it explains the generation gap in IUD perception. People who came of age during or shortly after the Dalkon Shield era may carry well-intentioned but outdated fears. The safety profile of current IUDs has been studied extensively and is not in serious dispute.

Male LARC and the Future of Long-Acting Contraception

Almost all LARC development to date has focused on methods for people with uteruses. That is starting to change, at least in research labs. Work is underway on long-acting contraceptive options for men, including injections and implants that would suppress sperm production without permanent sterilization.²⁸ None of these are close to market. Male contraceptive trials have historically struggled with both funding and dropout rates due to side effects, which has slowed progress. But the concept of a reversible, long-acting method that a man could use and then have removed when ready to conceive is the same principle that has made IUDs and implants so successful. Whether that principle can be translated into a commercially available male product remains an open question, but the research pipeline is more active now than it has been in decades.

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