Abstract
Intrauterine devices (IUDs) are effective, reversible forms of contraception with high patient satisfaction and continuation. IUDs can be safely used by most women and should be considered the first-line method of contraception for all women. This descriptive review will discuss the clinical issues associated with IUDs – including management of side effects, noncontraceptive uses and insertion and removal. When the burdens of cost are removed, women are more likely to select and IUDs. Health policy changes that increase insurance coverage for contraception will improve access to IUDs. IUDs remain an underutilized form of contraception in USA and efforts to improve availability and access to long-acting reversible contraception methods is needed to optimize their use.
Keywords
The intrauterine device (IUD) is a highly reliable and safe form of contraception that is currently utilized by 15.5% of reproductive aged women worldwide and 7.7% of American women using contraception [1]. Along with contraceptive implants, IUDs offer long-acting reversible contraception (LARC) for women and are becoming an increasingly popular contraceptive method. In addition to their efficacy in preventing unintended pregnancy, the benefits of IUDs – including their use for emergency contraception (EC) and treatment for menorrhagia and endometrial hyperplasia – are also being realized. An additional benefit of IUDs is their reversible nature. Once removed, return of fertility is rapid with 82% of women able to achieve pregnancy in 6 months and 89% within 1 year of discontinuation [2].
However, despite their many benefits and cost–effectiveness, IUDs are an underutilized method of contraception in many parts of the world.
Types of IUDs & mechanism of action
The WHO estimates that over 160 million women worldwide use IUDs. Globally, the geographic distribution of IUD use is impacted by the economic, clinical and programmatic realities of IUD availability as well as cultural practice and acceptance of IUD. Two-thirds of all IUD users live in China, where 30% of women use an IUD while use in USA has historically lagged behind use in Europe and other industrialized nations. Current family planning programs and public health programs aim to increase access and use of IUDs and other LARC methods.
Two types of IUDs are available in USA – the copper (Cu-IUD) and the levonorgestrel (LNG-IUD). There is one Cu-IUD available in USA – the CuT380A, or Paragard© IUD (Teva Women's Health, Inc., Sellersville, PA, USA). Currently there are three LNG-IUDs available in USA, including the LNG-20 (Mirena©, Bayer HealthCare Pharmaceuticals, Inc., Wayne, NJ, USA and Liletta©, Actavis Pharma, Inc., Parsippany, NJ, USA) and LNG-14 (Skyla©, Bayer HealthCare Pharmaceuticals, Inc.) IUDs. The primary mechanism of action of all IUDs is to prevent fertilization [3].
The CuT380A-IUD became available in USA in 1988, and is the only available nonhormonal LARC method. It is currently approved for use for up to 10 years after insertion, with evidence that it is effective for at least 12 years [4]. The contraceptive effects of the Cu-IUD are the result of the small quantities of copper ions that are continuously released from the device.
The first LNG-IUD to become available in USA in 2001 was LNG-20. The LNG-20 is approved for use up to 5 years after insertion and has likely effective for up to 7 years [5]. The LNG-20 contains 52 mg of levonorgestrel (LNG). It has an initial release rate of 20 μg LNG per 24 h that decreases with time, with an average dose of 14 μg LNG per 24 h after 5 years use. The small dose of active LNG has its primary action in the local environment of the uterus. Some systemic absorption occurs, and some women do not ovulate during the initial months of use. However, the primary contraceptive effect of the LNG-IUD is to prevent fertilization via thickening of the cervical mucus, inhibition of sperm mobility and ovum transport. In addition, the LNG acts locally in the endometrium where the hormonally responsive endometrial glands undergo atrophic changes that limit their proliferative ability. This effect on the endometrium explains the decrease in amount of bleeding experienced by most LNG-IUD users.
The LNG-14 IUD was approved for use in USA in 2013. It has the same mechanism of action as the LNG-20 IUD, but has a total LNG amount of 13.5 mg, with an initial daily dose of 14 μg every 24 h. It is approved for use up to 3 years. Compared with the Mirena IUD, Skyla is slightly smaller (28 × 30 mm vs 32 × 32 mm). Because of this, it is proposed that insertion may be easier for providers and more comfortable for nulliparous women.
In 2015, another LNG-20 option, the Liletta IUD, was approved for use in USA. The Liletta IUD contains 52 mg of LNG and is currently US FDA approved for use in pregnancy prevention for up to 3 years. Ongoing studies of Liletta are anticipated to demonstrate contraceptive efficacy for up to 6 years. Compared with the Mirena IUD, the Liletta does not offer clinical benefits, but manufacture-sponsored programs may reduce the cost of the device for some women [6]. Because upfront cost can be a barrier to IUD use for low-income or underinsured women, reducing the cost of the device has the potential to increase IUD uptake.
Benefits of IUDs: contraceptive efficacy & effectiveness, cost–effectiveness & continuation
Contraceptive efficacy refers to the how well a given birth control method prevents pregnancy when used consistently and correctly (perfect use), while contraceptive effectiveness refers to how well a given birth control method prevents pregnancy when used by the average person, who may not always use the method consistently or correctly (typical use). IUDs are very effective at preventing pregnancy in all users, with typical use failure rates of 0.2% for the LNG-IUDs and 0.8% for Cu-IUD, and perfect use failure rates of 0.2% for the LNG-IUDs and 0.6% for the Cu-IUD [7]. Among the most important contraceptive benefits of IUDs (and LARC options in general) is that, unlike barrier methods or most other contraceptive options, they are ‘forgettable’. They do not rely on patient adherence to prevent pregnancy [8]. For this reason, the contraceptive efficacy and effectiveness are very similar for IUDs.
The superior effectiveness of LARC methods, including IUDs and implants, to other hormonal methods is demonstrated by studies such as the Contraceptive CHOICE project, the largest cohort study of LARC use published to date. This study found a 20-fold increase in unintended pregnancy for women using oral contraceptive pills (OCPs), the transdermal patch or the vaginal ring when compared with women who used an LARC method [9]. Most (83%) LARC users in this cohort had chosen an IUD [10]. Teen pregnancy rates and abortion rates were also lower in the study cohort than in comparison groups [11]. These findings highlight how increased use of IUDs is a key strategy to decrease rates of unintended pregnancy worldwide [12].
The cost–effectiveness of LARC methods is superior to all other forms of contraception, even if used for less than a year. The significant upfront costs associated with IUDs have been barriers to their use for many women. The out-of-pocket cost of IUD insertion may approach several hundred US dollars for some women. Women who are responsible for cost sharing for their contraceptive care are less likely to use an IUD compared with alternative reversible contraceptive methods with less upfront costs like OCPs [13]. The Affordable Care Act of 2010 has mandated insurance coverage for contraception. The impact of this change in healthcare funding on uptake of IUDs is unknown, although recent research demonstrates that when cost is removed as a factor in contraceptive decision-making, women commonly select long-acting methods [10].
The state of California provides an interesting example of how enhanced contraceptive coverage for low-income women and through employment-based health insurance can impact contraceptive method choice. In California, where Medicaid expansions have helped provide free contraception and the Contraceptive Equity Act has mandated employer–sponsor health insurance cover many FDA-approved contraceptives, the rate of IUD use is higher than the national average and growing [14]. This example suggests that as more women have access to insurance coverage for IUDs under the Affordable Care Act, more women will chose to IUDs for contraception.
The effectiveness of contraception relies not only on correct and consistent use, but also patient acceptance and continuation of the method. Estimation of continuation rates after 1 year of initiating use for various birth control methods is determined from national surveys and clinical trials. Rates for reversible methods range broadly with LARC methods having the highest continuation rates. The 1-year respective continuation rates for Cu-IUDs and LNG IUDs are 78 and 80% respectively. Combined OCPs, the contraceptive ring and patch have 1-year continuation rates of 67% [15].
Considerations when counseling women: safety, side effects & risks
When counseling a woman who wishes to select a contraceptive method, a careful consideration of a woman's past medical, obstetrical and gynecologic history must be balanced with her family planning goals and expectations of her chosen method. IUDs are safe contraceptive methods for most women. The Centers for Disease Control [16] and the WHO have established Medical Eligibility Criteria (MEC) for Contraceptive Use that provide evidence-based guidance on contraceptive use and safety (see
Medical eligibility criteria guidance for intrauterine device use.
Consider the Cu-IUD as the ideal method in the following conditions: current breast cancer, positive or unknown APLA antibodies in the setting of SLE, history of coronary vascular accident, known thrombogenic mutation, multiple risk factors for cardiovascular disease, ischemic heart disease.
β-hCG: β-human chorionic gonadotropin; APLA: Antiphospholipid antibodies; ART: Antiretroviral therapy; IUD: Intrauterine device; LNG: Levonorgestrel; PID: Pelvic inflammatory disease; SLE: Systemic lupus erythematosus; STI: Sexually transmitted infection.
Side effects
The primary side effect women experience with both the LNG and Cu-IUDs is a change in menstrual bleeding patterns. Through suppression of endometrial growth, the LNG-IUD causes a thinning of the endometrium within 3 months of insertion. The irregular bleeding experienced by some women after initiation of an LNG-IUD is most common in the first 6 months and bleeding patterns typically diminish over time with a reduction of menstrual blood loss for 90% of users. Fifty percent of LNG-20 users are amenorrheic 1–2 years after insertion [18].
While the minority of LNG-IUD users report systemic side effects, emerging evidence suggests wide variability in the serum LNG levels in women. Correlation between reported systemic side effects and these variations in LNG levels have not been clearly linked in individual patients [19]. While the clinical management of LNG-IUD side effects includes use of nonsteroidal antinflammatory drugs), short courses of combined OCPs and doxycycline, well-designed studies are needed to develop evidence-based recommendations.
For the Cu-IUD, the most common side effect and reason for discontinuation is increased menstrual bleeding. Unlike the bleeding side effects experienced by LNG-IUD users, there is evidence that increased menstrual bleeding with Cu-IUDs persists with time [20]. Management with nonsteroidal antinflammatory drugs (like ibuprofen 800 mg orally every 8 h) during menses may help for those who experience increased uterine cramping and bleeding associated with Cu-IUD use.
When IUD users experience irregular or changes in bleeding pattern, ruling out expulsion or perforation and confirming the IUD location is important. Evaluation for alternative causes for abnormal uterine bleeding should be performed if indicated.
Uterine perforation
The rate of uterine perforation with IUD insertion is 0.4 per 1000 devices. Lactation, amenorrhea and insertion within 6 months of delivery have been found to increase risk of perforation [21]. Determining the position of the uterus with bimanual exam prior to insertion is important and use of a tenaculum to grasp the cervix and provide gentle traction has been found to reduce the uterocervical angle, straighten the uterus and theoretically make IUD insertion safer and less traumatic [22]. Clinical features of uterine perforation include mild to significant pain during and after insertion and abnormal vaginal bleeding, although perforation can be painless and 30% of women are asymptomatic [23]. Diagnostic evaluation should be initiated in the when patients have clinical symptoms of uterine perforation, when missing IUD strings are noted, or in the setting of pregnancy after IUD insertion. Evaluation in these situations starts with pelvic ultrasound to determine if the IUD is located in the uterus followed by abdominal x-ray to confirm intraperitoneal location if an intrauterine IUD is not seen on ultrasound. Management of confirmed uterine perforation with an IUD located in the abdomen or pelvis includes surgical exploration and removal, generally via a laparoscopic approach.
IUD insertion: who & how
IUD insertion can reasonably be offered to most women – including nulliparous women, adolescents, women undergoing abortion or women in the postpartum period. Historical barriers to IUD use in adolescents and women with history of sexually transmitted infections (STIs) and ectopic pregnancies have been refuted by research that proves the safety of IUDs in these populations. Currently the American College of Obstetricians and Gynecologists promotes the use of IUDs as an optimal contraceptive option in a wide array of women, including adolescents and nulliparous women [24]. Ultimately, increasing uptake of IUDs will include addressing current barriers to IUD insertion.
IUDs & sexually transmitted infections
Many providers use a two-visit insertion protocol that serves as a barrier to more widespread use of IUDs for many women. When two visits are required, up to 50% of women do not return for the IUD insertion [25]. Stated rationales for a two-visit insertion protocol include need to exclude current STIs and pregnancy at the time of IUD insertion and billing restrictions. However, evidence shows that it is not necessary to screen for STIs prior to IUD insertion in low risk women, and even same-day screening (i.e., at the time of IUD placement) for high-risk women is acceptable [26]. Even in women with current STIs at the time of IUD insertion, the risk for developing pelvic inflammatory disease (PID) is low. Diagnosing and treating STI in a timely fashion will reduce the risk of PID, and need not be done at an arbitrary interval prior to IUD insertion. Thus, in most cases, the benefit of continuation of an IUD during antibiotic treatment for an STI outweighs the risks of IUD removal for most women. As always, appropriate patient counseling is indicated [16,17].
IUD use in adolescents & nulliparous women
The historical connection between the early generation IUDs and PID combined with concerns about difficulty of insertion in nulliparous women have historically contributed to reluctance to use IUDs in teens and adolescent women. USA continues to have higher rates of teen pregnancy than many other industrialized countries. Additionally, the significant risks associated with teenage pregnancy including diminished educational attainment, poverty and adverse pregnancy outcomes, continue to disproportionately impact racial minorities and women who are socioeconomically disadvantaged in USA. Teenage pregnancy is a significant public health problem worldwide.
While the risk for PID associated with IUD use does have an inverse relationship to patient age, even in women aged 15–24 who have increased risk for STIs, the overall risk for PID in the setting of IUD use is 1.6 per 1000 woman-years of use. Additionally, several randomized and cohort studies demonstrate that the risk for PID associated with IUD use is elevated only in the 20 days following insertion [27].
Postplacental IUD insertion, as will be discussed, could have particular importance given the increased risk for closely spaced repeat pregnancy in teen mothers. Additionally, to increase IUD use in adolescents, a 1-day insertion protocol is important to optimize uptake.
A second concern regarding the use of IUDs in teens and nulliparous women relates to difficulty with insertion. However, clinical experience with IUD insertion in this population has demonstrated safety, high rates of satisfaction and continuation. American College of Obstetricians and Gynecologists now recommends IUDs and other LARC methods as the first-line contraceptive method for all women, including adolescents [28]. The management of difficult IUD insertions in nulliparous women or patients with cervical stenosis remains challenging. Clinical options include referral to a trained family planning specialist, use of ultrasound, insertion in settings where sedation is possible, use of a paracervical nerve block or use of misoprostol for cervical softening prior to insertion. Of these options, clear recommendations for optimal management in nulliparous women remains unknown. For instance, misoprostol has not been shown to have an effect on provider assessment of difficulty of IUD insertion [29] or patient discomfort [30] and no significant change in patient perception of pain was achieved with paracervical block [31]. The utility of ultrasound to assist with challenging insertions appears the literature as a recognized tool to aid in challenging insertions, but has not been systematically studied.
IUD insertion: when
Postabortion
Women undergoing elective abortion represent a group at high risk for unintended pregnancy. For women who have surgical abortion, immediate postabortal insertion of an IUD is an effective and acceptable intervention, with high patient satisfaction and continuation rates [32]. After medical abortion, IUD insertion has been found to be safe and effective with high continuation rates [33]. In this population, immediate postabortion IUD insertion should be considered, as interval placement performed 4–6 weeks after an abortion is demonstrated to have lower insertion rates than immediate placement [34]. While data on postabortion IUD expulsion rates vary, there does appear to be an increased likelihood of IUD expulsion related to increased gestational age at the time of abortion [35]. This should be balanced against the chance of non-placement if the woman does not return for subsequent visits. For women with evidence of endometritis or septic abortion, postabortal IUD insertion should be delayed until appropriate antibiotic treatment is completed and clinical resolution is verified.
Postplacental
Insertion of both copper and LNG-IUDs within 10 min of placental delivery in vaginal and cesarean delivery have been established as safe and acceptable [36–38]. The importance of effective contraception during the postpartum period is well established. Benefits extend beyond the prevention of unintended pregnancy to the decreased risk for short birth intervals, which are associated with increased maternal and neonatal morbidity. Recognizing the benefits of immediate postpartum LARC provision, several US states have changed their funding practices to improve reimbursement for LARC initiation prior to hospital discharge [39]. Even where postplacental IUD insertion is not feasible, interval postpartum insertion of IUDs improves with comprehensive antenatal counseling [40].
Risks associated with postplacental IUD insertion include increased risk for expulsion and perforation. Overall, risk of expulsion with postplacental IUD insertion remains varied across studies, but post placental insertion and insertion between 10 min and 48 h postpartum is associated with increased risk of expulsion when compared to interval insertion at 4–6 weeks postpartum [38]. Risk for expulsion is increased with vaginal delivery compared with cesarean section, but the effects of uterotonics and other predictors of expulsion are yet to be clarified [41]. Continuation rates are similar between postplacental insertion and to interval IUD placement [41].
In addition to an increased risk for expulsion, postpartum IUD insertion is associated with elevated risk for uterine perforation. While the overall perforation risk for both LNG and Cu-IUD appears to be ∼1 in 1000, placement within 6 months of delivery, during lactation and in women who are amenorrheic are recognized risk factors [21]. While no studies have specifically evaluated the benefit of ultrasound guidance in this setting, when feasible, use of ultrasound is reasonable to ensure appropriate placement. Women with chorioamnionitis during labor or uterine cavity abnormalities are not candidates for postplacental IUD placement.
Copper IUD as emergency contraception
EC offers an opportunity for prevention of pregnancy after unprotected intercourse has occurred. Currently, the Cu-IUD and selected oral hormonal methods are licensed and available for EC in USA. Of these, the Cu-IUD is the most effective form of EC, with a pregnancy rate of 1 in 1000 insertions [42].
The Cu-IUD can be inserted within 5 days after unprotected intercourse, and when the date of ovulation can be estimated [43]. Unlike oral EC methods that work by delaying or preventing ovulation, the mechanisms of action of the Cu-IUD for EC are to prevent fertilization by impacting sperm viability and function, to prevent formation of a viable gamete and prevent implantation by making the uterine endometrium nonreceptive via an inflammatory response [44].
The Cu-IUD has several benefits over the oral EC methods (ECP). First, ECP are only effective if taken before the peak of the LH surge, and thus have lower efficacy in the fertile window than the Cu-IUD [45]. Second, unlike oral EC methods, the Cu-IUD maintains efficacy as EC in women who are overweight and obese. And finally, if placed for EC, the Cu-IUD provides long-acting effective contraception for the woman.
While the practicality of Cu-IUD insertion limits its more widespread use as EC, it should be more widely promoted as the first-line EC treatment for women who want long-acting contraception.
IUD removal: management of missing strings & pregnancy
IUD removal can be safely done in an outpatient setting in most cases. When IUD strings are missing or in the rare case of an IUD in place during early pregnancy, additional considerations are necessary. Correct placement of an IUD can be confirmed with visualization or palpation of the IUD strings from the cervix. When strings are not present, the first step is to counsel the woman to use alternative contraception until the location of the IUD can be confirmed. When strings are not visible, a pelvic ultrasound should be done to assess if the IUD is in the uterus. Both types of IUD (LNG and copper) are visible on ultrasound, although the copper appears more echogenic. If not visualized on pelvic ultrasound, a pelvic x-ray can confirm location of the IUD in the pelvis. Both LNG and copper IUDs are radio-opaque, and can be seen in a 2D view on a pelvic radiograph. This may not confirm correct 3D placement in the uterus, but is helpful in identifying extrauterine placement.
Removal of an IUD that is in the uterus with no strings visible can be accomplished with the use of an IUD hook or thin forceps that are used to carefully explore the cervix and lower uterine segment to grasp the strings. If removal is not accomplished with this, hysteroscopy can be used to identify and remove the IUD. If perforation is confirmed and the IUD is found to be outside of the uterus, exploratory laparoscopy and removal is recommended.
Many minor cervical or transcervical procedures, such as endometrial biopsy, colposcopy and cervical conization or loop electrical excision procedures, can be accomplished with IUDs in place. In the case of excisional procedures, operative technique can be modified to avoid cutting the IUD string.
Pregnancies among women with an IUD are uncommon. Pregnancy with an IUD in situ can occur either secondary to failure of the IUD to provide contraception, or in the setting of IUD insertion during an undiagnosed luteal phase pregnancy. It is important to counsel women about the failure rate of IUDs, and to rule out pregnancy if they have symptoms that suggest pregnancy or if the location of the IUD is unknown.
While all women who conceive with an IUD in place have increased risk for adverse pregnancy outcomes including spontaneous abortion, septic abortion, preterm delivery and chorioamnionitis, women with retained IUDs appear to be at the greatest risk of these adverse outcomes [46]. Removal of the IUD as early as possible in the pregnancy is recommended by the both WHO and the FDA.
Noncontraceptive benefits of IUDs
The sustained release of LNG offers noncontraceptive benefits to women who use these IUDs. LNG-IUDs are associated with fewer bleeding days and lighter bleeding for a significant portion of users. The suppressive effect of the progestin on the endometrial lining can be associated with a 90% decrease in menstrual blood loss. In fact, the Mirena IUD is FDA approved for the management of menorrhagia. The LNG-IUD has been studied and found beneficial for women with chronic amenorrhea from other medical conditions as well as gynecologic disorders like menorrhagia and dysmenorrhea [47,48].
In addition to the benefits observed for women with idiopathic menorrhagia, the benefits of the LNG-20 in management of endometrial hyperplasia are now recognized. In women with typical hyperplasia, treatment with an LNG-IUD has been associated with a 90% chance of endometrial regression, and may be superior to oral therapy [49,50]. These findings suggest benefit of the LNG-IUD as a protective measure in obese women, who are at particular risk for endometrial hyperplasia and cancer.
In addition to the protective effect of LNG on the endometrium, there is evidence to suggest that use of Cu-IUDs may be associated with a decreased risk for invasive cervical cancer. The Oxford-Family Planning Association Contraceptive study is a large prospective cohort study of over 17,000 women who used oral contraceptives, diaphragms and IUDs. A nested case–control study with in this cohort demonstrated no relationship between risk for invasive cervical cancer and inert (noncopper) IUDs while suggesting a protective effect related to duration of use of Cu-IUDs [51]. While this study did not include women with LNG-IUDs, there are no data that suggest association between LNG IUDs and risk for invasive cervical cancer.
Conclusion
IUDs are effective contraceptive options with favorable side-effect profile and high patient satisfaction and continuation rates. Along with implants, IUDs are the most cost-effective, reversible birth control options available. Cu-IUDs are the only nonhormonal LAC method available and can be used for EC. By suppression of the endometrium lining, LNG-IUDs decrease bleeding and can be used to treat menorrhagia and endometrial hyperplasia in some women. Because they have few contraindications, IUDs can be safely used by most women. Increasing IUD use among adolescents and in women after childbirth and abortion can decrease unintended pregnancy rates. As health policy changes remove financial burdens and improve insurance coverage for IUDs, more women are likely to use IUDs.
Future perspective
As clear evidence mounts for the clinical and public health benefits of LARC methods, our understanding of how to optimize use of IUDs will continue to improve. In the coming years, further study of the non-contraceptive benefits of IUDs and elucidation of optimal post placental IUD insertion techniques are needed. Reproductive health policy needs to evolve with growing scientific evidence about the many benefits of improving access to LARC, particularly to vulnerable women. However, while enthusiasm about the many benefits of IUDs grows, providers need to maintain respect for reproductive autonomy to ensure women receive unbiased and fair contraceptive counseling free from coercion.
Executive summary
Intrauterine devices (IUDs) are a safe and effective form of birth control with noncontraceptive benefits.
Because of their contraceptive efficacy and high continuation rates, the American College of Obstetricians and Gynecologists recommends IUDs as the first-line method of contraception for all women, including nulliparous women and adolescents.
IUDs remain an underutilized form of contraception in USA. Efforts to improve availability and access to long-acting reversible contraception methods are needed to optimize their use.
Footnotes
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
No writing assistance was utilized in the production of this manuscript.
