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Hormonal intrauterine device

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IntraUterine System or IUD with progestogen
Background
TypeIntrauterine
First use1990 (Mirena - currently available)
1976 (Progestasert - discontinued in 2001)
Failure rates (first year (Mirena))
Perfect use0.2%
Typical use0.2%
Usage
Duration effect5 years (Mirena) 3 years (Skyla)
Reversibility2–6 months
User remindersCheck thread position monthly
Clinic reviewAnnually
Advantages and disadvantages
STI protectionNo
PeriodsCauses menstrual irregularity, periods are usually lighter or none at all (amenorrhea)
WeightNo proven effect
BenefitsNo need to remember to take any daily action
RisksOvarian cysts (usually benign)
Transient risk PID, Rare risk of uterine perforation

The intrauterine device (IUD) with progestogen is a hormonal intrauterine device classified as a long-acting reversible contraceptive method. It is one of the most effective forms of birth control.[1] In the United Kingdom, the IUD with progestogen is referred to as an intrauterine system (IUS) or intrauterine contraceptive (IUC). This article will refer to these devices as the hormonal IUD. Mirena is one brand name available in the United States.

The Device

The hormonal IUD is a small 'T'-shaped piece of plastic, which contains levonorgestrel, a type of progestogen.[2] The cylinder of the device contains the hormone and is coated with a membrane that regulates the release of levonorgestrel.[3] Mirena releases the hormone at an initial rate of 20 micrograms per day and declines to a rate of 14 micrograms after 5 years, which is still in the range of clinical effectiveness. Skyla releases 14 micrograms per day and declines to 5 micrograms per day after 3 years.[4] In comparison, oral contraceptives can contain 150 micrograms of levonorgestrel.[5] The hormonal IUD releases the levonorgestrel directly into the uterus. Most of the hormone stays inside the uterus, and only a small amount is absorbed into the rest of the body.[5]

Insertion and Removal

Correctly inserted IUD

The hormonal IUD is inserted in a similar procedure to the nonhormonal copper IUD, and can only be inserted by a qualified medical practitioner.[5] Before insertion, a pelvic exam is performed to examine the shape and position of the uterus. It is also recommended that patients be tested for gonorrhea and chlamydia prior to insertion, as a current STI at the time of insertion can increase the risk of pelvic infection.[6] During the insertion, the vagina is held open with a speculum, the same device used during a pap smear.[5] A grasping instrument is used to steady the cervix, the length of the uterus is measured for proper insertion, and the IUD is placed using a narrow tube through the opening of the cervix into the uterus.[5] A short length of monofilament plastic/nylon string hangs down from the cervix into the vagina. The string allows physicians and patients to check to ensure the IUD is still in place and enables easy removal of the device.[5] Mild to moderate cramping can occur during the procedure, which generally takes five minutes or less.

After insertion Mirena is effective for 5 years, although some studies have shown that it may be effective through 7 years.[7] Skyla is effective for 3 years.[4] Removal of the device should also be performed by a qualified medical practitioner. After removal, fertility will return to previous levels relatively quickly.[8] One study found that the majority of participants returned to fertility within three months.[9]

Insertion can be performed immediately postpartum and post-abortion if no infection has occurred.[10]

Effectiveness

The hormonal IUD is considered to be a long-acting reversible contraceptive, among the most effective forms of birth control. The first year failure rate for the hormonal IUD is .2% and the five year failure rate is .7%.[2] These rates are comparable to tubal sterilization, but the effects of the hormonal IUD are reversible.

The hormonal IUD is considered to be more effective than other common forms of reversible contraception, such as the birth control pill, because it requires little to no action by the user after insertion.[1] The effectiveness of other forms of birth control is mitigated by the users themselves. If medication regimens for contraception are not followed precisely, the method becomes less effective. IUDs require no daily, weekly, or monthly regimen, so their typical use failure rate is therefore the same as their perfect use failure rate.[1]

Mechanisms of Action

The hormonal IUD's primary mechanism of action is to prevent fertilization.[5][11][12][13][14] The levonorgestrel intrauterine system has several contraceptive effects:

  • Cervical mucus thickens[7]
  • Sperm's survival and ability to penetrate the egg is inhibited[15]
  • Endometrium is suppressed[16][17]
  • In some women, ovulation is inhibited[18]

Numerous studies have demonstrated that IUDs primarily prevent fertilization, not implantation.[5] In one experiment involving tubal flushing, fertilized eggs were found in half of women not using contraception, but no fertilized eggs were found in women using IUDs.[19] IUDs also decrease the risk of ectopic pregnancy, which further implies that IUDs prevent fertilization.[5]

Clinical uses

Use of the hormonal IUD for various medical conditions should be discussed with a qualified medical practitioner.

Advantages and Disadvantages of Use

Advantages

  • Is one of the most effective forms of reversible birth control[1]
  • It can be used while breastfeeding[10]
  • Nothing to do right before sex to make it work
  • Ability to become pregnant returns quickly when removed
  • Fewer menstrual cramps
  • Lighter periods and less blood (some women stop having periods completely)
  • Effective for five years
  • Less likely to interact with other medications and safe for women with medical problems

Disadvantages

  • Irregular periods and spotting between periods often occurs after insertion, but this usually improves after 3 to 6 months
  • Cramping or backache can occur at insertion
  • Mild to moderate discomfort during insertion procedure

Side Effects and Contraindications

Side Effects

  • Irregular menstrual pattern: irregular bleeding and spotting is common in the first 3 to 6 months of use. After that time periods become shorter and lighter, and 20% of women stop having periods after 1 year of use.[25]
  • Cramping and Pain: many women feel discomfort or pain during and immediately after insertion. Some women may have cramping for the first 1–2 weeks after insertion.[5]
  • Expulsion: Sometimes the IUD can slip out of the uterus. This is termed expulsion. Around 5% of IUD users experience expulsion. If this happens a woman is not protected from pregnancy.[5][26]
  • Perforation: Very rarely, the IUD can be pushed through the wall of the uterus during insertion. Risk of perforation is mostly determined by the skill of the practitioner performing the insertion. For experienced medical practitioners, the risk of perforation is 1 per 1,000 insertions or less.[27] If perforation does occur it can damage the internal organs, and in some cases surgery is needed to remove the IUD.
  • Pregnancy: Although the risk of pregnancy with an IUD is very small, if one does occur there is an increased risk of serious problems. These include ectopic pregnancy, infection, miscarriage, and early labor and delivery. Immediate removal the IUD is recommended in the case of pregnancy.[5][26]
  • Infection: The insertion of the IUD does have a rare risk of pelvic inflammatory disease (PID). Concurrent infection with gonorrhea or chlamydia at the time of insertion increases the risk of pelvic inflammatory disease.[28] If PID does occur, it will most likely happen within 21 days of insertion. The device itself does not increase the risk of infection.[5]
  • Ovarian Cysts: Enlarged follicles (ovarian cysts) have been diagnosed in about 12% of the subjects using a hormonal IUD. Most of these follicles are asymptomatic, although some may be accompanied by pelvic pain or dyspareunia. In most cases the enlarged follicles disappear spontaneously after two to three months. Surgical intervention is not usually required.[29]

A full list of possible side effects can be found on the Mirena website

Contraindications

A hormonal IUD should not be used by women who:[10]

  • Are, or think they may be, pregnant
  • Have abnormal vaginal bleeding that has not been explained
  • Have untreated cervical or uterine cancer
  • Have, or may have, breast cancer
  • Have certain abnormalities of the uterus
  • Have had pelvic inflammatory disease within the past 3 months
  • Have had an STI such as chlamydia or gonorrhea within the past 3 months
  • Have severe liver disease

A full list of contraindications can be found in the WHO Medical Eligibility Criteria for Contraceptive Use and the CDC United States Medical Eligibility Criteria for Contraceptive Use.[10][30]

History

The hormonal IUD came into existence following the creation of the copper IUD in the 1960s and 1970s.[31] Dr. Antonio Scommenga, working at the Michael Reese Hospital in Chicago, discovered that administering progesterone inside the uterus could have contraceptive benefits.[31] With knowledge of Scommegna's work, a Finnish doctor, Jouri Valter Tapani Luukkainen, created the 'T'-shaped IUD that released progesterone, marketed as the Progestasert System. This IUD had a short, 1-year lifespan and never achieved widespread popularity. Following this relative lack of success, Dr. Luukkainen replaced the progesterone with the hormone levonorgestrel to be released over a 5-year period, creating what is now Mirena.[32] In 2013 Skyla, a lower dose IUD effective for only 3 years, was approved by the FDA.[33]

See also

References

  1. ^ a b c d Winner, B; Peipert, JF; Zhao, Q; Buckel, C; Madden, T; Allsworth, JE; Secura, GM. (2012), "Effectiveness of Long-Acting Reversible Contraception", New England Journal of Medicine, 366 (21): 1998–2007, doi:10.1056/NEJMoa1110855{{citation}}: CS1 maint: multiple names: authors list (link)
  2. ^ a b [1], Bayer Pharmaceuticals.
  3. ^ Luukkainen, T. (1991), "Levonorgestrel-Releasing Intrauterine Device", Annals of the New York Academy of Sciences, 262: 43–49
  4. ^ a b Highlights of Prescribing Information (Report). 9 January 2013.
  5. ^ a b c d e f g h i j k l m Dean, Gillian; Schwarz, Eleanor Bimla (2011). "Intrauterine contraceptives (IUCs)". In Hatcher, Robert A.; Trussell, James; Nelson, Anita L.; Cates, Willard Jr.; Kowal, Deborah; Policar, Michael S. (eds.). Contraceptive technology (20th revised ed.). New York: Ardent Media. pp. 147–191. ISBN 978-1-59708-004-0. ISSN 0091-9721. OCLC 781956734. p.150:

    Mechanism of action
    Although the precise mechanism of action is not known, currently available IUCs work primarily by preventing sperm from fertilizing ova.26 IUCs are not abortifacients: they do not interrupt an implanted pregnancy.27 Pregnancy is prevented by a combination of the "foreign body effect" of the plastic or metal frame and the specific action of the medication (copper or levonorgestrel) that is released. Exposure to a foreign body causes a sterile inflammatory reaction in the intrauterine environment that is toxic to sperm and ova and impairs implantation.28,29 The production of cytotoxic peptides and activation of enzymes lead to inhibition of sperm motility, reduced sperm capacitation and survival, and increased phagocytosis of sperm.30,31… The progestin in the LNg IUC enhances the contraceptive action of the device by thickening cervical mucus, suppressing the endometrium, and impairing sperm function. In addition, ovulation is often impaired as a result of systemic absorption of levonorgestrel.23
    p. 162:
    Table 7-1. Myths and misconceptions about IUCs
    Myth: IUCs are abortifacients. Fact: IUCs prevent fertilization and are true contraceptives.
  6. ^ Mohllajee, AP; Curtis, KM; Herbert, PB. (2006), "Does insertion and use of an intrauterine device increase the risk of pelvic inflammatory disease among women with sexually transmitted infection? A systematic review", Contraception, 73 (2): 145–153{{citation}}: CS1 maint: multiple names: authors list (link)
  7. ^ a b Sivin, I; Stern, J; Coutinho, E; Mattos, CE; el Mahgoub, S; Diaz, S; et al. (1991), "Prolonged intrauterine contraception: a seven-year randomized study of the levonorgestrel 20 mcg/day (LNg 20) and the Copper T380 Ag IUDS", Contraception, 44: 473–480 {{citation}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  8. ^ Mansour, D; Gemzell-Danielsson, K; Inki, Pirjo; Jensen, JT. (2011), "Fertility after discontinuation of contraception: a comprehensive review of the literature", Contraception, 84 (5): 465–477{{citation}}: CS1 maint: multiple names: authors list (link)
  9. ^ Randic, L; Vlasic, S; Matrljan, I; Waszak, C (1985), "Return to fertility after IUD removal for planned pregnancy", Contraception, 32 (3): 253–259{{citation}}: CS1 maint: multiple names: authors list (link)
  10. ^ a b c d Centers for Disease Control and Prevention (2010), United States Medical Eligibility Criteria for Contraceptive Use. {{citation}}: Unknown parameter |html= ignored (help)
  11. ^ Ortiz, María Elena; Croxatto, Horacio B. (2007). "Copper-T intrauterine device and levonorgestrel intrauterine system: biological bases of their mechanism of action". Contraception. 75 (6 Suppl): S16‒S30. doi:10.1016/j.contraception.2007.01.020. PMID 17531610. {{cite journal}}: Unknown parameter |month= ignored (help) p. S28:

    Conclusions
    Active substances released from the IUD or IUS, together with products derived from the inflammatory reaction present in the luminal fluids of the genital tract, are toxic for spermatozoa and oocytes, preventing the encounter of healthy gametes and the formation of viable embryos. The current data do not indicate that embryos are formed in IUD users at a rate comparable to that of nonusers. The common belief that the usual mechanism of action of IUDs in women is destruction of embryos in the uterus is not supported by empirical evidence. The bulk of the data indicate that interference with the reproductive process after fertilization has taken place is exceptional in the presence of a T-Cu or LNG-IUD and that the usual mechanism by which they prevent pregnancy in women is by preventing fertilization.
  12. ^ ESHRE Capri Workshop Group (2008). "Intrauterine devices and intrauterine systems". Human Reproduction Update. 14 (3): 197‒208. doi:10.1093/humupd/dmn003. PMID 18400840. {{cite journal}}: Unknown parameter |momth= ignored (help) p. 199:

    Mechanisms of action
    Thus, both clinical and experimental evidence suggests that IUDs can prevent and disrupt implantation. It is unlikely, however, that this is the main IUD mode of action, … The best evidence indicates that in IUD users it is unusual for embryos to reach the uterus.
    In conclusion, IUDs may exert their contraceptive action at different levels. Potentially, they interfere with sperm function and transport within the uterus and tubes. It is difficult to determine whether fertilization of the oocyte is impaired by these compromised sperm. There is sufficient evidence to suggest that IUDs can prevent and disrupt implantation. The extent to which this interference contributes to its contraceptive action is unknown. The data are scanty and the political consequences of resolving this issue interfere with comprehensive research.
    p. 205:
    Summary
    IUDs that release copper or levonorgestrel are extremely effective contraceptives... Both copper IUDs and levonorgestrel releasing IUSs may interfere with implantation, although this may not be the primary mechanism of action. The devices also create barriers to sperm transport and fertilization, and sensitive assays detect hCG in less than 1% of cycles, indicating that significant prevention must occur before the stage of implantation.
  13. ^ Speroff, Leon; Darney, Philip D. (2011). "Intrauterine contraception". A clinical guide for contraception (5th ed.). Philadelphia: Lippincott Williams & Wilkins. pp. 239–280. ISBN 978-1-60831-610-6. pp. 246–247:

    Mechanism of action
    The contraceptive action of all IUDs is mainly in the intrauterine cavity. Ovulation is not affected, and the IUD is not an abortifacient.58–60 It is currently believed that the mechanism of action for IUDs is the production of an intrauterine environment that is spermicidal.
    Nonmedicated IUDs depend for contraception on the general reaction of the uterus to a foreign body. It is believed that this reaction, a sterile inflammatory response, produces tissue injury of a minor degree but sufficient enough to be spermicidal. Very few, if any, sperm reach the ovum in the fallopian tube.
    The progestin-releasing IUD adds the endometrial action of the progestin to the foreign body reaction. The endometrium becomes decidualized with atrophy of the glands.65 The progestin IUD probably has two mechanisms of action: inhibition of implantation and inhibition of sperm capacitation, penetration, and survival.
  14. ^ Jensen, Jeffrey T.; Mishell, Daniel R. Jr. (2012). "Family planning: contraception, sterilization, and pregnancy termination". In Lentz, Gretchen M.; Lobo, Rogerio A.; Gershenson, David M.; Katz, Vern L. (eds.). Comprehensive gynecology. Philadelphia: Mosby Elsevier. pp. 215–272. ISBN 978-0-323-06986-1. {{cite book}}: More than one of |editor= and |editor1-last= specified (help) p. 259:

    Intrauterine devices
    Mechanisms of action
    The common belief that the usual mechanism of action of IUDs in women is destruction of embryos in the uterus is not supported by empirical evidence... Because concern over mechanism of action represents a barrier to acceptance of this important and highly effective method for some women and some clinicians, it is important to point out that there is no evidence to suggest that the mechanism of action of IUDs is abortifacient.
    The LNG-IUS, like the copper device, has a very low ectopic pregnancy rate. Therefore, fertilization does not occur and its main mechanism of action is also preconceptual. Less inflammation occurs within the uterus of LNG-IUS users, but the potent progestin effect thickens cervical mucus to impede sperm penetration and access to the upper genital track. Although the LNG-IUS also produces a thin, inactive endometrium, there is no evidence to suggest that this will prevent implantation, and the device should not be used for emergency contraception.
  15. ^ Munuce, MJ; Nascimento, JAA; Rosano, G; Faundes, A; Bahamondes, L (2006), "Does of levonorgestrel comparable to that delivered by levonorgestrel-releasing uterine system can modify the in vitro expression of zona binding sites of human spermatozoa", Contraception, 73 (1): 97–101{{citation}}: CS1 maint: multiple names: authors list (link)
  16. ^ Silverberg, SG; Haukkamaa, M; Arko, H, Nilsson, CG; Luukkainen, T (1986), "Endometrial morphology during long-term use of levonorgestrel-releasing intrauterine devices", Int. J. Gynecol. Pathol., 5 (3): 235–241{{citation}}: CS1 maint: multiple names: authors list (link)
  17. ^ Guttinger, A; Critchley, HO (2007), "Endometrial effects of intrauterine levonorgestrel", Contraception, 75 (6 Suppl.): S93–S98{{citation}}: CS1 maint: multiple names: authors list (link)
  18. ^ Sivin, I; Schmidt, F. (1987), "Effectivenss of IUDs: a review", Contraception, 36: 55–84{{citation}}: CS1 maint: multiple names: authors list (link)
  19. ^ Alvarez, F; Brache, V.; Fernandez, E; Guerrero, B; Guiloff, E; Hess, R; et al. (1988), "New insights on the mode of action of intrauterine contraceptive devices in women", Fertil Steril, 49: 768–773 {{citation}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  20. ^ a b c Luis Bahamondes, M Valeria Bahamondes, Ilza Monteiro. (2008), "Levonorgestrel-releasing intrauterine system: uses and controversies.", Expert Review of Medical Devices, 4: 437{{citation}}: CS1 maint: multiple names: authors list (link)
  21. ^ Petta C, Ferriani R, Abrao M, Hassan D, Rosa E Silva J, Podgaec S, Bahamondes L (2005). "Randomized clinical trial of a levonorgestrel-releasing intrauterine system and a depot GnRH analogue for the treatment of chronic pelvic pain in women with endometriosis". Hum Reprod. 20 (7): 1993–8. doi:10.1093/humrep/deh869. PMID 15790607.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  22. ^ Sheng, J; Zhang, WY; Zhang, JP; Lu, D. (2009), "The LNG-IUS study on adenomyosis: a 3-year follow-up on the efficacy and side effects of the use of levonorgestrel intrauterine system for the treatment of dysmenorrheal associated with adenomyosis", Contraception, 79 (3): 189–193{{citation}}: CS1 maint: multiple names: authors list (link)
  23. ^ Faundes A, Alvarez F, Brache V, Tejada A (1988). "The role of the levonorgestrel intrauterine device in the prevention and treatment of iron deficiency anemia during fertility regulation". Int J Gynaecol Obstet. 26 (3): 429–33. doi:10.1016/0020-7292(88)90341-4. PMID 2900174.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  24. ^ Marjoribanks J, Lethaby A, Farquhar C (2006). Marjoribanks, Jane (ed.). "Surgery versus medical therapy for heavy menstrual bleeding". Cochrane Database Syst Rev (2): CD003855. doi:10.1002/14651858.CD003855.pub2. PMID 16625593.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  25. ^ Hidalgo, M; Bahomondes, L; Perrottie, M; Diaz, J; Dantas-Monterio, C; Petta, CA. (2002), "Bleeding Patterns and clinical performance of the levonorgestrel-releasing intrauterine device (Mirena) up to two years", Contraception, 65 (2): 129–132{{citation}}: CS1 maint: multiple names: authors list (link)
  26. ^ a b Population Information Program, John Hopkins School of Public Health (1995), "IUDs—An Update", Population Reports, XXII (5)
  27. ^ World Health Organization (1987), Mechanisms of action, safety and efficacy of intrauterine devices: technical report series 753., Geneva{{citation}}: CS1 maint: location missing publisher (link)
  28. ^ Grimes, DA (2000), "Intrauterine Device and upper-genital-tract infection", The Lancet, 356: 1013–1019
  29. ^ Bahamondes L, Hidalgo M, Petta CA, Diaz J, Espejo-Arce X, Monteiro-Dantas C. (2003), "Enlarged ovarian follicles in users of a levonorgestrel-releasing intrauterine system and contraceptive implant", J. Reproduc. Med., 48 (8): 637–640{{citation}}: CS1 maint: multiple names: authors list (link)
  30. ^ WHO (2010). "Intrauterine devices (IUDs)". Medical Eligibility Criteria for Contraceptive Use (4th ed.). Geneva: Reproductive Health and Research, WHO. ISBN 978 92 4 1563888. {{cite book}}: External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
  31. ^ a b Thiery, M (1997), "Pioneers of the intrauterine device", The European Journal of Contraception and Reproductive Healthcare, 2 (1): 15–23
  32. ^ Thiery, M (2000), "Intrauterine contraception: from silver ring to intrauterine implant", Journal of Obstetrics & Gynecology and Reproductive Biology, 90: 145–152
  33. ^ [FDA drug approval for Skyla]

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