Abstract

Intrauterine devices (IUDs) represent a cornerstone of modern contraception, offering highly effective, long-acting, and reversible protection against unintended pregnancies. This comprehensive report provides an exhaustive examination of IUDs, delving into their intricate historical development, diverse classifications, nuanced mechanisms of action, robust efficacy rates, potential side effects and rare complications, meticulous insertion and removal procedures, precise patient suitability criteria, and the varied landscape of their global adoption patterns. By synthesizing a wealth of current research, clinical guidelines from authoritative bodies, and empirical data, this report aims to furnish healthcare providers, policymakers, and patients with an unparalleled understanding of IUDs, thereby facilitating profoundly informed decision-making in reproductive healthcare.

1. Introduction

Reproductive health stands as a fundamental pillar of individual well-being and societal progress, intrinsically linked to the ability of individuals and couples to determine the timing and spacing of their children. Contraception is an indispensable tool in achieving these objectives, empowering individuals to prevent unintended pregnancies, mitigate maternal and infant mortality, and foster greater autonomy over their reproductive lives. Within the expansive spectrum of available contraceptive methodologies, intrauterine devices (IUDs) have ascended to a preeminent position, largely attributed to their exceptional efficacy, commendable safety profile, and unparalleled user convenience. Defined as small, T-shaped devices meticulously designed for insertion into the uterine cavity, IUDs exert their contraceptive effects locally within the uterus. Their evolution traces back centuries, with rudimentary forms documented as early as the ancient world, though modern IUDs emerged in the early 20th century, undergoing significant refinements in material, design, and mechanism throughout the latter half of the century. The paradigm shift towards long-acting reversible contraceptives (LARCs), which include IUDs and contraceptive implants, has underscored their critical role in reducing unintended pregnancy rates globally due to their inherent ‘set it and forget it’ nature, eliminating issues of user adherence. IUDs are broadly dichotomized into two principal categories: copper IUDs, which operate non-hormonally, and hormonal IUDs, which release a progestin. This report embarks upon an exhaustive exploration of the intricate characteristics, multifaceted mechanisms, documented efficacy, spectrum of side effects, detailed procedural aspects, rigorous patient suitability considerations, and prevailing global perspectives associated with these highly effective contraceptive technologies.

2. Types of Intrauterine Devices

IUDs are systematically classified based on their fundamental composition and their primary mode of contraceptive action, leading to two distinct yet equally effective categories: copper IUDs and hormonal IUDs. Understanding the nuances of each type is crucial for tailored patient counseling and optimal contraceptive outcomes.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

2.1 Copper IUDs

Copper IUDs, often referred to as non-hormonal IUDs, represent a significant advancement in contraceptive technology, having been developed in the 1960s with the recognition that adding copper to an inert device significantly enhanced its contraceptive efficacy. The most widely recognized and extensively studied copper IUD globally is the TCu 380A, commonly marketed under brand names such as Paragard in the United States or Eurogine in Europe, among others. Its design typically features a polyethylene T-frame with copper wire coiled around the vertical arm and copper sleeves on the horizontal arms, providing a total copper surface area of 380 mm². Other copper IUD designs exist, such as Nova-T and GyneFix, which may vary in shape, copper surface area, and duration of efficacy, but they operate on similar fundamental principles.

The primary mechanism of action for copper IUDs is multifactorial and predominantly pre-fertilization. The presence of copper within the uterine environment initiates a series of biochemical and cellular responses that collectively create a milieu highly hostile to both sperm and ova. Specifically, the device continuously releases minute quantities of copper ions (Cu2+) into the uterine and tubal fluids. These copper ions act as potent spermicides, fundamentally impairing sperm function in several critical ways:

• Impaired Sperm Motility and Viability: Copper ions significantly reduce sperm motility (their ability to swim) and viability (their capacity to survive). This is achieved by affecting sperm metabolism, membrane integrity, and enzymatic activity essential for their journey through the female reproductive tract. Sperm become less agile and are rapidly immobilized, rendering them incapable of reaching the fallopian tubes for fertilization. Research, such as studies cited by the World Health Organization (WHO), consistently demonstrates the direct toxic effect of copper on sperm, leading to their rapid demise within the uterus [WHO, 2015].
• Inhibition of Sperm Capacitation and Acrosome Reaction: Beyond simple motility, copper ions interfere with the physiological processes of sperm capacitation and the acrosome reaction. Capacitation is a crucial maturation process that sperm undergo in the female reproductive tract, enabling them to fertilize an egg. The acrosome reaction, a prerequisite for fertilization, involves the release of enzymes that allow sperm to penetrate the egg’s outer layers. Copper ions disrupt these biochemical pathways, effectively preventing sperm from acquiring the capacity to fertilize an ovum [United Nations Population Fund (UNFPA), 2021].
• Leukocyte Infiltration and Inflammatory Response: The presence of the copper IUD within the uterus induces a localized, sterile inflammatory reaction within the endometrium. This is characterized by an increase in the number of white blood cells (leukocytes), particularly macrophages, neutrophils, and lymphocytes, as well as elevated levels of prostaglandins and other inflammatory mediators within the uterine and tubal fluids. These inflammatory cells contribute to the spermicidal effect by phagocytosing (engulfing) sperm and altering the uterine environment, making it even more inimical to sperm survival and function [Ortiz & Croxatto, 1987; National Institute for Health and Care Excellence (NICE), 2020].
• Alteration of Endometrial Lining: While the primary contraceptive action is pre-fertilization, the inflammatory response also causes a subtle but significant alteration to the endometrial lining. This creates an unfavorable environment for potential implantation of a fertilized egg, should fertilization rarely occur despite the primary spermicidal effect. It is crucial to emphasize that this endometrial alteration is a preventative measure against implantation and does not disrupt an already implanted pregnancy. The consensus among major medical organizations (e.g., American College of Obstetricians and Gynecologists [ACOG], WHO) is that IUDs are not abortifacients because their primary action occurs before implantation [ACOG, 2017].

The TCu 380A copper IUD is highly durable, offering effective contraception for up to 10 to 12 years, making it one of the longest-acting reversible contraceptive methods available. This extended duration contributes significantly to its cost-effectiveness and user satisfaction, as it requires minimal ongoing intervention after insertion.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

2.2 Hormonal IUDs

Hormonal IUDs represent a distinct category that leverages the localized release of a synthetic progestin, levonorgestrel (LNG), directly into the uterine cavity. The development of hormonal IUDs began in the 1970s, with the first LNG-releasing IUD (LNg-20) introduced in the 1970s, leading to the widely adopted Mirena in the 1990s. This targeted delivery minimizes systemic hormonal exposure while maximizing local contraceptive effects, thereby reducing the likelihood of systemic side effects commonly associated with oral contraceptive pills or injectables. Currently, several hormonal IUDs are available, differentiated primarily by their size, total LNG content, and daily release rate, which in turn influences their duration of efficacy:

• Mirena (Bayer): Contains 52 mg of LNG, initially releasing approximately 20 micrograms per day. Approved for 8 years of contraception and is also indicated for the treatment of heavy menstrual bleeding (menorrhagia) and as part of hormone therapy for perimenopausal and postmenopausal women [FDA, 2021].
• Kyleena (Bayer): Contains 19.5 mg of LNG, initially releasing approximately 17.5 micrograms per day. Approved for 5 years of contraception and is smaller than Mirena, potentially offering a more comfortable fit for nulliparous women [FDA, 2021].
• Liletta (Medicines360/Allergan): Contains 52 mg of LNG, similar to Mirena, initially releasing approximately 18.6 micrograms per day. Approved for 8 years of contraception and also indicated for menorrhagia [FDA, 2021].
• Skyla / Jaydess (Bayer): Contains 13.5 mg of LNG, initially releasing approximately 14 micrograms per day. Approved for 3 years of contraception and is the smallest of the currently available hormonal IUDs [FDA, 2021].

The primary mechanisms of action for hormonal IUDs are predominantly localized within the uterus and cervix, effectively creating an environment inimical to fertilization and implantation:

• Thickening of Cervical Mucus: The most significant and consistent contraceptive effect of LNG-IUDs is the dramatic thickening of cervical mucus. Levonorgestrel alters the consistency and quantity of mucus produced by the cervical glands, rendering it highly viscous and impenetrable to sperm. This thickened mucus acts as a physical barrier, effectively blocking sperm passage from the vagina into the uterus and fallopian tubes, thereby preventing fertilization [World Health Organization (WHO), 2015].
• Suppression of Endometrial Growth: LNG-IUDs induce marked changes in the endometrial lining, leading to glandular atrophy, decidualization of the stroma, and a reduction in endometrial thickness. This suppression of endometrial proliferation makes the uterine lining unsuitable for implantation, even if fertilization were to rarely occur. This endometrial effect is also the basis for their therapeutic use in treating menorrhagia, as the thinned lining significantly reduces or even eliminates menstrual bleeding over time. Many users of LNG-IUDs experience lighter periods, sporadic spotting, or even amenorrhea (absence of menstruation) [FSRH Clinical Guideline, 2019].
• Inhibition of Sperm Capacitation and Motility: While less pronounced than with copper IUDs, the localized presence of LNG can also directly affect sperm viability and function within the uterus, further contributing to the hostile uterine environment [FSRH Clinical Guideline, 2019].
• Partial or Complete Ovulation Inhibition (Less Primary): While not the primary mechanism, particularly with lower-dose LNG-IUDs, the systemic absorption of levonorgestrel, even at very low levels, can sometimes suppress ovulation in some cycles. The higher-dose LNG-IUDs (e.g., Mirena, Liletta) are more likely to partially or completely inhibit ovulation compared to lower-dose devices (e.g., Kyleena, Skyla). However, even when ovulation occurs, the combined effects on cervical mucus and the endometrium provide highly effective contraception. This mechanism is considered secondary to the local uterine effects [FSRH Clinical Guideline, 2019].

Hormonal IUDs offer a duration of efficacy ranging from 3 to 8 years, depending on the specific device, providing prolonged contraception and often offering non-contraceptive benefits, particularly for managing heavy menstrual bleeding.

3. Mechanisms of Action: A Deeper Dive

The profound efficacy of IUDs as contraceptive agents is underpinned by a sophisticated interplay of biological and mechanical mechanisms. While superficially categorized into hormonal and non-hormonal types, a detailed understanding of their multifaceted actions reveals how both designs converge on the ultimate goal of preventing pregnancy.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

3.1 Copper IUDs: A Chemical and Inflammatory Barrier

The contraceptive effect of copper IUDs is predominantly mediated through a series of local intrauterine reactions, occurring primarily before fertilization takes place. These mechanisms are summarized and expanded upon below:

• Spermicidal Action via Copper Ions: The continuous release of copper ions (Cu2+) into the uterine and tubal fluids is central to the copper IUD’s efficacy. These ions are highly toxic to sperm, disrupting their physiological functions at multiple levels:
  • Decreased Sperm Motility (Hypermotility to Immotility): Copper ions interfere with sperm’s cellular respiration and ATP production, which are crucial for flagellar movement. This leads to impaired progressive motility, rendering sperm unable to traverse the cervical mucus and ascend the uterine cavity and fallopian tubes to meet an ovum. Initially, some studies suggest a transient period of hypermotility followed by rapid immotility, but the overall effect is a significant reduction in motile sperm reaching the ovum [Marik & Grana, 2002].
  • Compromised Sperm Viability: Copper ions damage sperm cell membranes and DNA, leading to reduced sperm lifespan and viability. This structural and functional damage means that even if sperm were to reach the ovum, their capacity for fertilization would be severely diminished [Ortiz & Croxatto, 1987].
  • Inhibition of Capacitation and Acrosome Reaction: Copper also disrupts the complex biochemical cascade required for sperm capacitation, the physiological maturation process that occurs in the female reproductive tract enabling sperm to fertilize an egg. Furthermore, it inhibits the acrosome reaction, a crucial enzymatic event that allows sperm to penetrate the egg’s outer layers. Without successful capacitation and acrosome reaction, fertilization is effectively prevented [Stanford University, 2023].
• Localized Sterile Inflammatory Response: The presence of the copper IUD, combined with the release of copper ions, induces a localized, non-infectious inflammatory reaction within the endometrium and uterine fluids. This response is characterized by:
  • Leukocyte Infiltration: A significant influx of white blood cells, including macrophages, neutrophils, and lymphocytes, occurs in the uterine cavity. These cells contribute to the overall hostility of the uterine environment by phagocytosing (engulfing) sperm and potentially unfertilized ova. They also release inflammatory mediators that further impair sperm function [Alperstein, 2019].
  • Increased Prostaglandins and Enzymes: The inflammatory process elevates levels of prostaglandins (e.g., PGF2α) and various hydrolytic enzymes within the endometrial tissue and uterine secretions. These substances contribute to the spermicidal effect, interfere with oocyte transport, and create an unfavorable biochemical environment for sperm survival and fertilization [Ortiz & Croxatto, 1987].
• Disruption of Oocyte Transport: Although a lesser primary mechanism, the inflammatory changes and altered uterine and tubal motility induced by the copper IUD may also subtly affect oocyte transport, further reducing the chances of fertilization [WHO, 2015].
• Endometrial Changes for Implantation Prevention: While the primary action is pre-fertilization, should any sperm manage to survive and fertilize an egg, the copper IUD’s effects on the endometrium prevent implantation. The sterile inflammation and resulting changes in the uterine lining make it unsuitable for an embryo to attach and develop. This is a crucial distinction: copper IUDs prevent implantation, they do not terminate an existing pregnancy [ACOG, 2017].

Many thanks to our sponsor Esdebe who helped us prepare this research report.

3.2 Hormonal IUDs: A Localized Hormonal Barrier

Hormonal IUDs, by contrast, exert their contraceptive effects primarily through the localized and continuous release of levonorgestrel (LNG), a synthetic progestin. This targeted delivery minimizes systemic exposure while profoundly altering the local reproductive environment:

• Cervical Mucus Thickening: This is arguably the most consistent and critical mechanism of LNG-IUDs. Levonorgestrel induces a profound change in the quantity and viscosity of cervical mucus, rendering it thick, scant, and impermeable to sperm. The mucus forms an impenetrable plug in the cervical canal, physically blocking sperm from ascending into the uterine cavity and fallopian tubes, thereby preventing fertilization [FSRH Clinical Guideline, 2019].
• Endometrial Suppression and Atrophy: LNG directly acts on the endometrial lining, inducing significant morphological and biochemical changes. These include:
  • Glandular Atrophy: The endometrial glands become inactive and atrophic.
  • Decidualization of Stroma: The stromal cells undergo decidualization, transforming into large, polygonal cells similar to those seen in early pregnancy, but in a non-functional, suppressed state.
  • Reduced Endometrial Thickness: The overall thickness of the endometrium is significantly reduced. These changes create an environment that is profoundly inhospitable to implantation, even if fertilization were to occur [Bayer HealthCare Pharmaceuticals, 2021 (Mirena prescribing information)]. This mechanism is also responsible for the common side effect and therapeutic benefit of reduced menstrual bleeding and amenorrhea.
• Impaired Sperm Motility and Survival within the Uterus: While less potent than copper, LNG can also directly affect sperm within the uterine cavity, further reducing their viability and ability to fertilize an egg [FSRH Clinical Guideline, 2019].
• Partial or Complete Ovulation Inhibition (Dose-Dependent): While the local effects are primary, a small amount of LNG is absorbed systemically. The extent of systemic absorption and its impact on ovulation can vary with the specific LNG-IUD device and individual patient response. Higher-dose LNG-IUDs (e.g., Mirena, Liletta) may suppress ovulation in a proportion of cycles (e.g., 10-20% for Mirena), while lower-dose devices (e.g., Kyleena, Skyla) generally allow ovulation to occur more consistently. Even when ovulation does occur, the primary cervical mucus and endometrial effects provide highly effective contraception. Therefore, while ovulation inhibition can contribute, it is not considered the main contraceptive mechanism for most LNG-IUDs, distinguishing them from combined oral contraceptives that primarily suppress ovulation [FSRH Clinical Guideline, 2019].
• Tubal Motility and Function: Some research suggests that LNG may also subtly alter the motility and function of the fallopian tubes, potentially interfering with gamete transport, though this is considered a minor contributory mechanism [NICE, 2020].

In essence, both types of IUDs create a highly effective physical and biochemical barrier within the female reproductive tract, meticulously designed to prevent the successful journey of sperm to an ovum, or, failing that, the implantation of a fertilized egg, thus offering robust pregnancy prevention.

4. Efficacy Rates

IUDs stand out as among the most effective, if not the most effective, reversible contraceptive methods available worldwide, rivaling surgical sterilization in their effectiveness and significantly surpassing user-dependent methods such as oral contraceptive pills, patches, rings, condoms, or diaphragms. Their status as long-acting reversible contraceptives (LARCs) contributes to their high ‘typical use’ effectiveness rates, as they require minimal ongoing user adherence after insertion.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

4.1 Copper IUD Efficacy

The TCu 380A copper IUD is renowned for its exceptional effectiveness. Its first-year failure rate is remarkably low, typically ranging from 0.6% to 0.8% in typical use, with some studies reporting failure rates as low as 0.1-0.5% in perfect use scenarios [Trussell, 2011; Contraception, 2017]. This translates to a pregnancy rate of less than 1 woman per 100 users in the first year. Over its extended lifespan of up to 10-12 years, the cumulative failure rate remains exceedingly low, approximately 2% or less, demonstrating sustained efficacy over its long duration of action [WHO, 2015].

• Emergency Contraception: A unique and critical aspect of the copper IUD’s efficacy is its role as the most effective form of emergency contraception. When inserted within 5 days (120 hours) of unprotected sexual intercourse, the TCu 380A IUD can reduce the risk of pregnancy by over 99.9%. This makes it significantly more effective than oral emergency contraceptive pills, including levonorgestrel or ulipristal acetate, as it acts primarily by preventing fertilization or implantation, rather than delaying ovulation [ACOG, 2015; Faculty of Sexual and Reproductive Healthcare (FSRH), 2017]. This is a crucial point for patient counseling, as many individuals are unaware of this highly effective emergency option.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

4.2 Hormonal IUD Efficacy

Hormonal IUDs also boast exceptionally high efficacy rates, comparable to those of copper IUDs and sterilization. The specific failure rates can vary slightly depending on the device and its LNG dosage:

• Mirena / Liletta (High-Dose LNG-IUDs): These devices have a first-year failure rate of approximately 0.1-0.2% in typical use, making them among the most effective contraceptive methods available. This translates to fewer than 2 pregnancies per 1000 users in the first year. Over their approved lifespan of 8 years, the cumulative failure rate remains similarly low [Bayer HealthCare Pharmaceuticals, 2021 (Mirena prescribing information); FDA, 2021].
• Kyleena (Medium-Dose LNG-IUD): Kyleena exhibits a first-year failure rate of approximately 0.29%, making it highly effective over its 5-year duration [Bayer HealthCare Pharmaceuticals, 2021 (Kyleena prescribing information)].
• Skyla / Jaydess (Low-Dose LNG-IUD): Skyla has a first-year failure rate of approximately 0.4%, providing reliable contraception over its 3-year lifespan [Bayer HealthCare Pharmaceuticals, 2021 (Skyla prescribing information)].

Overall, the efficacy of both copper and hormonal IUDs is largely independent of user compliance once inserted, which is a major advantage over methods requiring daily, weekly, or monthly action. This inherent ‘set it and forget it’ nature contributes significantly to their superior effectiveness in real-world settings compared to methods that are highly susceptible to human error or non-adherence. For context, typical use failure rates for oral contraceptive pills range from 7-9%, and for condoms, they can be as high as 13-18% [Trussell, 2011], highlighting the significant advantage of IUDs in preventing unintended pregnancies.

5. Side Effects and Complications

While IUDs are generally considered safe and well-tolerated, like all medical interventions, they are associated with certain side effects and, rarely, more serious complications. Comprehensive counseling on these potential occurrences is paramount for informed patient decision-making and ongoing satisfaction.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

5.1 Common Side Effects

The most frequently reported side effects are typically confined to the uterine environment and are directly related to the specific type of IUD.

5.1.1 Copper IUDs

• Heavier and Longer Menstrual Bleeding (Menorrhagia): This is the most common side effect associated with copper IUDs. The sterile inflammatory response induced by copper can lead to increased prostaglandin production in the endometrium, which in turn can cause uterine contractions and increased blood flow to the uterine lining. This often results in menstrual periods that are heavier (increased blood volume) and/or longer in duration (e.g., lasting more than 7 days) [ACOG, 2017]. This effect is usually most pronounced in the first few months after insertion and may gradually lessen but often persists for the duration of use. Management strategies include non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen, taken during menstruation, which can reduce both bleeding and pain. Antifibrinolytic agents like tranexamic acid can also be highly effective in reducing menstrual blood loss [NICE, 2020].
• Increased Menstrual Cramps (Dysmenorrhea): Similar to menorrhagia, copper IUDs can exacerbate or induce uterine cramping during menstruation. This is thought to be due to increased prostaglandin levels causing stronger uterine contractions. Like bleeding, cramping is often most bothersome in the initial months and can persist. NSAIDs are the first-line treatment for managing IUD-related dysmenorrhea [ACOG, 2017].
• Intermenstrual Spotting: Some users may experience irregular spotting between periods, particularly in the first few cycles post-insertion, which typically resolves spontaneously.

5.1.2 Hormonal IUDs

• Irregular Bleeding Patterns: This is the most common and often expected side effect of hormonal IUDs, especially in the initial 3-6 months post-insertion. The localized release of levonorgestrel thins the endometrial lining, leading to unpredictable shedding patterns. This can manifest as:
  • Spotting: Light bleeding or brownish discharge, often intermittent.
  • Oligomenorrhea: Infrequent periods.
  • Amenorrhea: Complete cessation of menstrual bleeding. Many users (e.g., 20-50% for Mirena by 1 year) will experience amenorrhea, which is considered a safe and often desired non-contraceptive benefit [Bayer HealthCare Pharmaceuticals, 2021]. Patients should be counseled that these changes are normal and typically not indicative of a problem. Over time, bleeding patterns usually become lighter and more predictable, or periods may cease entirely.
• Hormonal Side Effects (Minimal Systemic Absorption): Due to the localized action and minimal systemic absorption of LNG, systemic side effects are generally less common and less severe than with oral hormonal contraceptives. However, some individuals may experience:
  • Headaches: Mild to moderate headaches.
  • Nausea: Infrequent and usually transient.
  • Breast Tenderness: Mild breast discomfort.
  • Mood Changes: Some individuals report mood fluctuations, including irritability or low mood, although definitive causal links are harder to establish given the numerous factors affecting mood. These symptoms, if they occur, are typically mild and often resolve within the first few months as the body adjusts [FSRH Clinical Guideline, 2019].
  • Acne: A potential androgenic effect of progestins, some users may experience new or worsening acne.
• Functional Ovarian Cysts: Hormonal IUDs can sometimes lead to the development of functional ovarian cysts (follicular cysts), which are typically benign, asymptomatic, and resolve spontaneously within 1-3 months. Rarely, they may cause pelvic pain or rupture [Bayer HealthCare Pharmaceuticals, 2021].

5.1.3 Common to Both IUD Types

• Pain/Cramping during Insertion: Both types of IUDs require transcervical insertion, which can cause varying degrees of pain, cramping, or discomfort during the procedure and for several hours to days afterward. This is typically managed with over-the-counter pain relievers (e.g., NSAIDs) taken prior to or immediately after insertion [ACOG, 2017].

Many thanks to our sponsor Esdebe who helped us prepare this research report.

5.2 Rare Complications

While generally safe, IUDs are associated with a low risk of more serious complications. Comprehensive counseling must include a discussion of these rare but significant events.

• Expulsion: Partial or complete expulsion of the IUD from the uterus occurs in a small percentage of users. Rates vary, but approximately 2-10% of IUDs may be expelled within the first year, with lower rates thereafter [Teal & Romer, 2019]. Risk factors for expulsion include: insertion immediately postpartum (especially within the first 4-6 weeks), nulliparity, history of severe dysmenorrhea, previous IUD expulsion, and heavy menstrual bleeding. Patients are typically instructed to check for the presence of the IUD strings regularly (e.g., after each period) to ensure the device is in place. Symptoms of expulsion may include cramping, unusual bleeding, or feeling the IUD itself. If expulsion is suspected, a healthcare provider should be consulted immediately for assessment, removal if partial, and discussion of replacement or alternative contraception. If unnoticed, expulsion can lead to an unintended pregnancy [NICE, 2020].

• Uterine Perforation: This is the most serious, albeit rare, complication, occurring when the IUD punctures or penetrates the uterine wall during insertion. The incidence of perforation is very low, typically reported as 1-2 per 1000 insertions, though some studies suggest rates as low as 0.1-0.2 per 1000 [Heinemann et al., 2015; Committee Opinion No. 735, 2018]. Risk factors for perforation include: provider inexperience, insertion in a breastfeeding woman (due to uterine softening), insertion postpartum (especially within 6 months due to uterine involution), uterine retroversion, and anatomical uterine anomalies. Symptoms can range from severe abdominal pain at insertion (if recognized immediately) to being asymptomatic, with the IUD migrating into the abdominal cavity. Management typically involves surgical retrieval of the device, often via laparoscopy. If a perforation is suspected, imaging (ultrasound, X-ray, or CT scan) is performed to locate the IUD, followed by appropriate surgical intervention if the IUD is extra-uterine [NICE, 2020].

• Pelvic Inflammatory Disease (PID): The risk of PID is not increased in long-term IUD users who are not at risk for sexually transmitted infections (STIs). The risk of PID is primarily confined to the first 20 days (approximately 3 weeks) following IUD insertion, and this increased risk is almost exclusively associated with the insertion process itself, particularly if the woman has a pre-existing, undiagnosed STI (e.g., Chlamydia or Gonorrhea) at the time of insertion [Curtis & Ellerston, 2019]. The IUD strings do not act as wicks for infection. Therefore, STI screening prior to IUD insertion is often recommended, especially for individuals at high risk for STIs. Symptoms of PID include pelvic pain, fever, unusual vaginal discharge, and pain during intercourse. PID is treated with antibiotics, and in severe cases, removal of the IUD may be considered, though it is not always necessary if treatment is prompt [ACOG, 2017].

• Ectopic Pregnancy: IUDs are highly effective at preventing all pregnancies, including ectopic pregnancies. However, if a pregnancy does occur while an IUD is in place (which is rare due to the high efficacy), there is a relatively higher chance (approximately 50%) that such a pregnancy will be ectopic (implanting outside the uterus, most commonly in the fallopian tube) compared to pregnancies in women not using contraception. It is crucial to emphasize that the absolute risk of ectopic pregnancy is significantly lower in IUD users than in women not using any contraception because IUDs reduce the overall risk of pregnancy so effectively. For instance, the absolute risk of ectopic pregnancy is approximately 1 per 1000 women per year in IUD users, compared to 6-8 per 1000 women per year in women using no contraception [ACOG, 2017]. Any woman with an IUD who experiences symptoms of pregnancy (e.g., missed period, positive pregnancy test) or abdominal pain should be evaluated promptly for ectopic pregnancy.

• Pregnancy with IUD in situ: Although rare, a pregnancy can occur with an IUD still in the uterus. If this happens, there is an increased risk of complications such as miscarriage (especially septic miscarriage), preterm labor and delivery, and chorioamnionitis (infection of the amniotic fluid and membranes). If a woman becomes pregnant with an IUD in place, the IUD should be removed if the strings are visible and removal is feasible without invading the gestational sac. Removing the IUD significantly reduces the risk of miscarriage and infection. If the strings are not visible, or removal would disrupt the pregnancy, the IUD may be left in place, but the patient must be closely monitored for complications [ACOG, 2017].

6. Insertion and Removal Procedures

IUD insertion and removal are typically quick, outpatient procedures performed by trained healthcare providers in a clinical setting. While generally straightforward, a meticulous approach and adequate patient preparation are essential for minimizing discomfort and ensuring successful placement or retrieval.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

6.1 Pre-Procedure Considerations for Insertion

Prior to IUD insertion, several critical steps are undertaken to ensure patient safety and suitability:

• Comprehensive Counseling: Detailed discussion covering all aspects of the chosen IUD type, including mechanisms of action, efficacy rates, common side effects, rare complications, expected bleeding patterns, duration of action, and removal process. The advantages of LARCs and the ‘set it and forget it’ nature should be highlighted. Informed consent is obtained.
• Medical History Review: Assessment for absolute and relative contraindications (e.g., pregnancy, active pelvic infection, unexplained vaginal bleeding, certain cancers, Wilson’s disease for copper IUD, current breast cancer for hormonal IUD). The provider should inquire about allergies and any history of fainting, vasovagal reactions, or anxiety related to gynecological procedures.
• Pregnancy Test: A negative pregnancy test is mandatory to rule out existing pregnancy, as IUDs are contraindicated in pregnant women.
• STI Screening: While not an absolute prerequisite in all cases, STI screening (e.g., for Chlamydia and Gonorrhea) is highly recommended, particularly for individuals at increased risk of STIs. If an active STI is diagnosed, insertion should be delayed until after treatment completion to minimize the risk of post-insertion PID [CDC, 2021].
• Pain Management and Anxiety Reduction: Strategies to minimize discomfort are crucial. Patients are often advised to take an NSAID (e.g., ibuprofen 600-800 mg) 30-60 minutes prior to the procedure. Some clinics may offer local anesthetic (lidocaine) gel or injection, especially for nulliparous women or those with a history of severe dysmenorrhea. Creating a calm environment and providing reassurance can also significantly reduce anxiety [ACOG, 2017].
• Timing of Insertion: IUDs can be inserted at any time in the menstrual cycle, provided pregnancy has been ruled out. However, insertion during menstruation may be preferred by some providers as the cervix is often slightly softer and more open, potentially easing insertion. Immediate postpartum insertion (within 10 minutes of placental delivery) or delayed postpartum insertion (4-6 weeks after delivery) are also options, though immediate postpartum insertions have a higher expulsion rate but are highly convenient for the patient [FSRH Clinical Guideline, 2019].

Many thanks to our sponsor Esdebe who helped us prepare this research report.

6.2 Insertion Procedure

The insertion of an IUD is a sterile procedure that typically follows these steps:

1. Pelvic Examination: A bimanual pelvic examination is performed to assess uterine size, position (anteverted, retroverted), and mobility, and to rule out any uterine anomalies or tenderness that might contraindicate insertion. This helps guide the insertion process and reduces perforation risk.
2. Speculum Insertion and Cervical Cleansing: A speculum is inserted to visualize the cervix. The cervix and vaginal vault are then thoroughly cleansed with an antiseptic solution (e.g., povidone-iodine or chlorhexidine) to minimize infection risk.
3. Tenaculum Application: A tenaculum (a grasping instrument) is gently applied to the anterior lip of the cervix. This helps to stabilize the cervix, straighten the uterine canal (aligning the cervical canal with the uterine cavity), and provide gentle traction to reduce the angle for easier insertion. Patients should be warned of a sharp pinch or cramp with tenaculum application.
4. Uterine Sounding: A sterile uterine sound is carefully inserted through the cervical os into the uterine cavity until resistance is met at the fundus. This measures the depth and direction of the uterus, which is crucial for selecting the correct IUD size and ensuring proper placement to avoid perforation. The typical uterine depth for IUD insertion is 6-9 cm [ACOG, 2017].
5. IUD Preparation and Insertion: The IUD is removed from its sterile packaging and prepared according to the manufacturer’s instructions. Each IUD comes with an inserter tube. The IUD is loaded into the tube, and the flange on the inserter is set to the measured uterine depth. The inserter tube, with the IUD inside, is then carefully advanced through the cervical os and into the uterine cavity until the predetermined depth is reached. The IUD is released by withdrawing the inserter tube while holding the plunger, allowing the arms of the ‘T’ shape to unfold inside the uterus. For many modern IUDs, this involves a ‘withdrawal’ or ‘push-and-release’ technique where the outer tube is withdrawn while the inner plunger holds the IUD in place until it is fully deployed at the fundus [NICE, 2020].
6. String Trimming: Once the IUD is correctly positioned, the strings (typically made of fine nylon) attached to its base are trimmed to approximately 3-4 cm, leaving them long enough to be easily palpated by the patient and provider but short enough not to protrude from the vagina. The strings rest within the vagina or curl around the cervix.
7. Post-Insertion Assessment and Counseling: The speculum is removed. The patient is advised about expected cramping and bleeding. They are instructed on how to check their IUD strings (e.g., after each period or periodically) and warned about signs of expulsion or other complications. A follow-up visit (e.g., 4-6 weeks post-insertion or after the next menstrual period) is often recommended to confirm correct placement of the IUD and to address any concerns. During this visit, the provider may palpate the strings or perform an ultrasound if there are concerns about placement [ACOG, 2017].

Many thanks to our sponsor Esdebe who helped us prepare this research report.

6.3 Removal Procedure

IUD removal is generally simpler and less painful than insertion, typically taking only a few minutes.

1. Speculum Insertion: A speculum is inserted to visualize the cervix.
2. String Visualization: The IUD strings are located protruding from the cervical os. If the strings are not visible, efforts are made to locate them. This may involve using a cytobrush or grasping forceps to gently probe the cervical canal, or, if unsuccessful, an ultrasound to confirm IUD presence and position. In rare cases where strings are not visible and the IUD is confirmed to be intra-uterine but deeply embedded, hysteroscopy (a procedure to visualize the uterine cavity with a camera) or dilation and curettage may be required for removal [Medscape, 2023].
3. Gentle Traction: Once the strings are identified, they are grasped firmly with a pair of long, narrow forceps. The IUD is then removed by applying steady, gentle traction to the strings. The arms of the IUD typically fold upwards as it is withdrawn through the cervix, minimizing discomfort. Patients may experience a brief cramp during removal [ACOG, 2017].
4. Post-Removal Counseling: After removal, the IUD is inspected to ensure it is intact. Patients are counseled on their options for immediate contraception (if desired, as fertility returns quickly), and any expected bleeding or discomfort. For those wishing to conceive, fertility typically returns rapidly, often within the first menstrual cycle after removal [FSRH Clinical Guideline, 2019].

7. Patient Suitability and Contraindications

One of the significant advantages of IUDs is their broad applicability to a diverse range of women, making them suitable for most individuals seeking contraception. However, a thorough medical assessment is crucial to identify any contraindications or specific considerations.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

7.1 General Suitability and Advantages

IUDs are recommended as a first-line contraceptive option for many populations due to their efficacy and safety:

• Adolescents: IUDs are highly suitable for adolescents. Despite past misconceptions, current guidelines from organizations like ACOG and the CDC recommend IUDs for teenagers due to their high efficacy, reduction in unintended pregnancies, and ease of use (no daily adherence required) [ACOG, 2017; CDC, 2021].
• Nulliparous Women (Women who have not given birth): Historically, IUDs were thought to be unsuitable for nulliparous women due to concerns about increased infection risk or difficulty of insertion. However, extensive research has debunked these myths. IUDs are now widely recognized as safe and effective for nulliparous women, and newer, smaller hormonal IUDs (e.g., Kyleena, Skyla) are often preferred for easier insertion in women with smaller uterine cavities. There is no evidence that IUD use in nulliparous women negatively affects future fertility [ACOG, 2017].
• Postpartum and Breastfeeding Women: IUDs can be safely inserted immediately postpartum (within 10 minutes of placental delivery) or at delayed postpartum visits. For breastfeeding women, both copper and hormonal IUDs are considered safe and do not impact milk supply or infant health. Copper IUDs are completely non-hormonal, and the minimal systemic absorption of LNG from hormonal IUDs poses no known risk to breastfeeding infants [WHO, 2015].
• Women with Medical Conditions: Many women with chronic medical conditions that might contraindicate other hormonal methods (e.g., combined oral contraceptives) can safely use IUDs. This includes women with certain cardiovascular conditions (like well-controlled hypertension, history of DVT/PE with no active disease), migraines (especially those with aura, where estrogen-containing methods are contraindicated), or liver conditions (provided they are not acute or cancerous) [FSRH Clinical Guideline, 2019].
• Emergency Contraception Candidates: As previously discussed, copper IUDs are the most effective form of emergency contraception and can then remain in place for ongoing highly effective contraception [ACOG, 2015].

Many thanks to our sponsor Esdebe who helped us prepare this research report.

7.2 Absolute Contraindications

Absolute contraindications mean that the IUD must not be inserted due to significant health risks or complete ineffectiveness. These include:

• Known or Suspected Pregnancy: IUDs are strictly contraindicated in pregnant women.
• Current Pelvic Inflammatory Disease (PID) or active sexually transmitted infection (STI), such as gonorrhea or chlamydia, or purulent cervicitis. Insertion must be postponed until the infection has been treated and resolved [CDC, 2021].
• Unexplained Vaginal Bleeding: Any unexplained abnormal vaginal bleeding must be investigated and a diagnosis established before IUD insertion, as it could be a symptom of a serious underlying condition (e.g., endometrial or cervical cancer).
• Uterine or Cervical Malignancy: Known or suspected cancer of the uterus or cervix. The IUD could interfere with diagnosis or treatment, and insertion could potentially disseminate cancer cells.
• Uterine Anomalies or Fibroids that Distort the Uterine Cavity: Significant uterine fibroids that distort the shape of the uterine cavity, or congenital uterine anomalies (e.g., bicornuate or septate uterus), can make IUD insertion difficult or impossible, increase the risk of expulsion or perforation, and may reduce efficacy [ACOG, 2017].
• Current Breast Cancer (for Hormonal IUDs): Hormonal IUDs release progestin, which is contraindicated in individuals with current or recent breast cancer, as some breast cancers are hormone-sensitive [FDA, 2021].
• Wilson’s Disease or Copper Allergy (for Copper IUDs): Wilson’s disease is a rare genetic disorder leading to copper accumulation in the body, making a copper IUD contraindicated. A severe, documented allergy to copper is also a contraindication [ACOG, 2017].

Many thanks to our sponsor Esdebe who helped us prepare this research report.

7.3 Relative Contraindications and Considerations

Relative contraindications or cautions mean that IUD insertion may be considered, but with careful assessment of risks and benefits, or after certain conditions are managed.

• History of Ectopic Pregnancy: A history of ectopic pregnancy is not a contraindication to IUD use. In fact, IUDs reduce the absolute risk of ectopic pregnancy compared to no contraception, though if a pregnancy occurs with an IUD in place, it is more likely to be ectopic. Careful counseling is necessary [FSRH Clinical Guideline, 2019].
• Immunosuppression/Valvular Heart Disease: While no longer considered absolute contraindications, individuals with severe immunosuppression (e.g., uncontrolled HIV with low CD4 count, organ transplant recipients) or complicated valvular heart disease historically received prophylactic antibiotics before IUD insertion due to theoretical concerns of endocarditis or infection. Current guidelines typically state that antibiotic prophylaxis is not routinely recommended for IUD insertion, even in these groups, as the risk is exceedingly low [ACOG, 2017; AHA, 2021].
• Severe Dysmenorrhea or Menorrhagia (for Copper IUDs): For women already suffering from very heavy or painful periods, a copper IUD may exacerbate these symptoms, potentially leading to dissatisfaction and early removal. In such cases, a hormonal IUD (which often improves these symptoms) or an alternative method might be more suitable [NICE, 2020].
• Postpartum Uterus: While IUDs can be inserted postpartum, immediate postpartum insertions (within 10 minutes of placental delivery) have a higher expulsion rate (around 10-25%) compared to interval insertions. Delayed postpartum insertion (e.g., 4-6 weeks after delivery) has lower expulsion rates but may be less convenient for the patient [Teal & Romer, 2019]. The risks and benefits of immediate vs. delayed insertion should be discussed.
• Cervical Stenosis: Severe cervical stenosis can make insertion difficult or impossible. In some cases, cervical dilation may be performed, or the procedure may need to be done under analgesia or sedation.

Ultimately, the decision to use an IUD should be a shared one between the patient and their healthcare provider, weighing the individual’s medical history, reproductive goals, lifestyle, and preferences against the specific benefits and risks of each IUD type.

8. Global Perspectives

Intrauterine device usage exhibits considerable geographical variation, reflecting diverse historical contexts, public health policies, socio-cultural factors, healthcare infrastructure, and prevailing perceptions among both providers and the general populace. Understanding these global trends is crucial for assessing the IUD’s role in global family planning efforts.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

8.1 Usage Trends and Disparities

Global data on contraceptive prevalence reveals stark differences in IUD uptake:

• High Prevalence Regions: IUDs account for a substantial proportion of contraceptive use in certain parts of the world. For instance, in China, IUDs have historically been the most prevalent method of contraception, largely influenced by government family planning policies that mandated or strongly encouraged their use during the one-child policy era. While policies have evolved, IUDs remain a dominant method due to established infrastructure, affordability, and widespread familiarity. Similarly, in many countries in Central Asia and parts of Eastern Europe (e.g., Ukraine, Kazakhstan, Russia), IUDs represent a significant percentage of contraceptive methods, often stemming from Soviet-era public health initiatives that prioritized long-acting methods [UNFPA, 2021; Darroch & Singh, 2013].
• Low Prevalence Regions: Conversely, IUD usage remains remarkably low in other significant regions, notably sub-Saharan Africa, many parts of Latin America, and historically, much of Western Europe and North America, although trends in the latter two are shifting. In sub-Saharan Africa, despite high unmet needs for family planning, IUD uptake is often limited by a combination of factors including cultural resistance, provider bias, lack of trained providers, limited awareness, and fears surrounding side effects or infertility [IPPF, 2019]. In parts of the Americas and Western Europe, historical controversies (e.g., the Dalkon Shield crisis in the 1970s which severely damaged public trust in IUDs in the US), provider misconceptions (e.g., IUDs are only for parous women), and strong preferences for daily oral contraceptives or condoms contributed to their underutilization for decades [ACOG, 2017; Holt et al., 2019].

Many thanks to our sponsor Esdebe who helped us prepare this research report.

8.2 Factors Influencing Global Uptake

Numerous complex factors contribute to the observed disparities in IUD usage:

• Policy and Programmatic Factors: National family planning policies significantly influence method mix. Countries with strong government commitment to long-acting methods, often supported by public health campaigns, provider training, and subsidized access, tend to have higher IUD prevalence. Conversely, lack of supportive policies or emphasis on short-acting methods can limit uptake [UNFPA, 2021].
• Provider Knowledge, Attitudes, and Skills: A significant barrier in many regions is inadequate provider training in IUD insertion and removal, coupled with persistent misconceptions among healthcare professionals themselves (e.g., that IUDs are unsuitable for nulliparous women, or concerns about PID risk). If providers are uncomfortable offering IUDs, or hold negative biases, access is severely curtailed. Addressing these gaps through comprehensive training and updated clinical guidelines is critical [Contraception, 2017; AAFP, 2014].
• Patient Awareness and Education: Many individuals, particularly in low-prevalence regions, lack accurate information about IUDs. Misinformation, myths (e.g., IUDs cause infertility, migrate throughout the body, or are abortifacients), and negative anecdotal experiences can deter uptake. Effective public health campaigns and patient education initiatives are essential to dispel these myths and promote informed choice [PMC, 2017].
• Accessibility and Cost: The upfront cost of an IUD and the insertion procedure can be a barrier, especially in low-income settings, even though IUDs are highly cost-effective over their lifespan. Availability of trained providers and accessible clinics, particularly in rural areas, also plays a crucial role. In countries with universal healthcare or robust insurance coverage, cost barriers are often mitigated [KFF, 2023].
• Cultural and Social Norms: In some societies, cultural norms or religious beliefs may influence contraceptive choices, sometimes favoring methods that are perceived as less invasive or less permanent. Partner approval or community acceptance can also play a role in method selection.
• Method Mix and Availability: The range of contraceptive options available in a country can also influence IUD uptake. Where a wide array of methods is readily available and promoted, IUDs may be one among many choices. In settings with limited options, IUDs may be a more prominent choice if accessible.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

8.3 Role of IUDs in Global Public Health

Despite disparities, IUDs hold immense potential for improving global reproductive health outcomes. Their attributes make them particularly valuable in addressing unmet needs for family planning and reducing unintended pregnancies worldwide:

• High Effectiveness: Their high efficacy translates directly to fewer unintended pregnancies, which in turn reduces rates of unsafe abortions and improves maternal and child health outcomes.
• Long-Acting Reversibility: The extended duration of action significantly reduces the need for frequent clinic visits or daily adherence, making them ideal for busy individuals, those with limited access to healthcare, or in contexts where supply chains for short-acting methods are unreliable.
• Cost-Effectiveness: While the upfront cost may be higher, their long lifespan makes IUDs one of the most cost-effective contraceptive methods over time, especially valuable for national health systems and individual users.
• Non-Contraceptive Benefits (Hormonal IUDs): The therapeutic benefits of hormonal IUDs for menorrhagia and dysmenorrhea are increasingly recognized, offering a dual advantage to users suffering from these conditions, thereby improving quality of life.

International organizations like the WHO, UNFPA, and USAID actively support programs to expand access to IUDs globally, recognizing their pivotal role in achieving global family planning goals and advancing reproductive rights. Efforts focus on training healthcare providers, ensuring supply chain management, and conducting targeted public awareness campaigns to overcome existing barriers and promote informed choice [WHO, 2015]. The growing acceptance and integration of IUDs, particularly in regions previously resistant, signify a promising trajectory for enhanced reproductive health worldwide.

9. Conclusion

Intrauterine devices (IUDs) stand as a testament to the ongoing advancements in reproductive healthcare, offering a highly effective, safe, and uniquely reversible contraceptive option for a vast and diverse population of women. Their distinct mechanisms, whether the spermicidal and inflammatory actions of copper or the localized hormonal effects of levonorgestrel, converge to provide robust protection against unintended pregnancies, often with significant non-contraceptive benefits, particularly in the case of hormonal IUDs. The exceptional efficacy rates, rivaling those of permanent sterilization, coupled with their long duration of action and minimal user dependence, position IUDs as a cornerstone of modern contraceptive practice.

While generally well-tolerated, a comprehensive understanding of their common side effects – such as changes in bleeding patterns for both types – and rare, albeit serious, complications like expulsion or uterine perforation, is paramount. Thorough patient counseling, encompassing these potential outcomes, alongside detailed instruction on insertion and removal procedures, forms the bedrock of patient safety and satisfaction. Furthermore, the growing evidence supporting the suitability of IUDs for a broad spectrum of individuals, including adolescents and nulliparous women, challenges outdated misconceptions and expands access to highly effective contraception for more individuals.

Globally, IUD utilization patterns reveal a complex interplay of historical, socio-cultural, economic, and policy-driven factors. Overcoming barriers such as provider knowledge gaps, patient misinformation, and access challenges is essential to unlock the full potential of IUDs in addressing unmet family planning needs worldwide. As a critical component of reproductive autonomy, accessible and accurate information about IUDs empowers individuals to make informed choices that align with their reproductive goals and overall well-being. Continued efforts in research, education, and healthcare infrastructure development will undoubtedly solidify the IUD’s indispensable role in advancing global public health and family planning initiatives.

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