Intrauterine device

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The modern intrauterine device (IUD) is a form of birth control in which a small 'T'-shaped device, containing either copper or progesterone, is inserted into the uterus. IUDs are a form of long-acting reversible contraception, which is the most effective type of reversible birth control.[1] As of 2002, IUDs were the most widely used form of reversible contraception, with nearly 160 million users worldwide.[2]

Contents

Types

The types of intrauterine devices available and the names they go by differ by location.

In the United States, there are two types available:[3]

In the United Kingdom, there are over 10 different types of copper IUDs available. In the UK, the term IUD refers only to these copper devices. Hormonal intrauterine contraception is considered to be a different type of birth control and is labeled with the term intrauterine system (IUS).[4][5]

However, the WHO/ATC labels both copper and hormonal devices as IUDs.

Copper

An IUD as seen on pelvic X ray

Copper IUDs primarily work by disrupting sperm mobility and damaging sperm so that they are prevented from joining with an egg. Copper acts as a natural spermicide within the uterus, increasing levels of copper ions, prostaglandins, and white blood cells within the uterine and tubal fluids.[6][7] The increased copper ions in the cervical mucus inhibit the sperm's motility and viability, preventing sperm from traveling through the cervical mucus or destroying it as it passes through.[8] Copper IUDs have a first year failure rate ranging from 0.1 to 2.2%.[9]

Most non-hormonal IUDs have a plastic T-shaped frame that is wound around with pure electrolytic copper wire and/or has copper collars (sleeves). The arms of the frame hold the IUD in place near the top of the uterus. The Paragard TCu 380a measures 32 mm (1.26") horizontally (top of the T), and 36 mm (1.42") vertically (leg of the T).

Copper IUDs containing noble metals are becoming increasingly popular because they are more resistant to corrosion. In the "Gold T IUD", which is made in Spain and Malaysia, there is a gold core, which further prevents the copper from fragmenting or corroding. GoldringMedusa is a differently-shaped German version of the Gold T [1].Another form of AuCu IUD is called Goldlily which is made by the Hungarian company, Radelkis. Goldlily consists of a layer of copper wires wrapped around an original layer of gold wires, and it provides electrochemical protection in addition to ionic protection.[2].

Silver IUDs also exist. Radelkis also makes Silverlily, which is similar to Goldlily, and GoldringMedusa is available in an AgCu version as well. Nova-T 380 contains a strengthening silver core, but does not incorporate silver ions themselves to provide electrochemical protection.

[4][10] Other shapes of IUD include the so-called U-shaped IUDs, such as the Load and Multiload, and the frameless IUD that holds several hollow cylindrical minuscule copper beads. It is held in place by a suture (knot) to the fundus of the uterus. It is mainly available in China, Europe, and Germany, although some clinics in Canada can provide it.

Advantages of the copper IUD include its ability to provide emergency contraception up to five days after unprotected sex. It is the most effective form of emergency contraception available.[11] It contains no hormones, so it can be used while breastfeeding, and fertility returns quickly after removal.[12] Copper IUDs are also available in a wider range of sizes and shapes than hormonal IUDs. Disadvantages include the possibility of heavier menstrual periods and more painful cramps.[6]

In addition to copper, noble metal and progestogen IUDs, patients in China can get copper IUDs with indomethacin. This non-hormonal compound reduces the severity of menstrual bleeding, and these coils are popular.[13]

Hormonal

The hormonal I.U.D. (brand name Mirena) does not increase bleeding as copper-containing IUDs do. Rather, they reduce menstrual bleeding or prevent menstruation altogether, and can be used as a treatment for menorrhagia (heavy periods).

Use of Mirena results in much lower systemic progestogen levels than other very-low-dose progestogen-only hormonal contraceptives.

As of 2007, the LNG-20 IUS – marketed as Mirena by Bayer – is the only IntraUterine System available. First introduced in 1990, it releases levonorgestrel (a progestin) and may be used for five years per its label but 7 years per researchers/clinicians. With use of Mirena, the hormones are localized to the uterine area unlike oral contraceptives and other systemic contraception (e.g. depot medroxyprogesterone, etonogestrel implant).

Mechanism

IUDs work by preventing fertilization rather than via preventing implantation.[14] Some within the antiabortion movement have claimed that IUDs are an abortifacient in an effort to decrease their use as a contraceptive, this position however is not supported by the evidence.[15]

History

The history of IUDs dates back to the interuterine devices of the early 1900s. Unlike IUDs, interuterine devices crossed both the vagina and the uterus, causing a high incidence of pelvic inflammatory disease in a time period when gonorrhea was endemic. The first IUD was developed by the German physician, Dr. Richter of Waldenburg. His device was made of silkworm gut and was not widely used.[16]

Dr. Ernst Gräfenberg, another German physician after whom the G-spot is named, created the first Ring IUD, Gräfenberg's ring, made of silver filaments. His work was suppressed during the Nazi regime, when contraception was considered a threat to Aryan women.[16] He moved to the United States, where his colleagues Dr. H. Hall and Dr. M. Stone took up his work after his death and created the stainless steel Hall-Stone Ring. A Japanese doctor named Tenrei Ota also developed a silver or gold IUD called the Precea or Pressure Ring.[16]

Dr. Jack Lippes helped begin the increase of IUD use in the United States in the late 1950s. In this time, thermoplastics, which can bend for insertion and retain their original shape, became the material used for first-generation IUDs. Lippes also devised the addition of the monofilament nylon string, which facilitates IUD removal. His trapezoid shape Lippes Loop IUD became one of the most popular first generation IUDs. In the following years, many different shaped plastic IUDs were invented and marketed.[16] These included the infamous Dalkon Shield, whose poor design caused bacterial infection and led to thousands of lawsuits. Although the Dalkon shield was removed from the market, it had a lasting, negative impact on IUD use in the United States.[17]

The invention of the copper IUD in the 1960s brought with it the capital 'T' shaped design used by most modern IUDs. US physician, Dr. Howard Tatum determined that the 'T' shape would work better with the shape of the uterus, which forms a 'T' when contracted. He predicted this would reduce rates of IUD expulsion.[16] Together, Tatum and Chilean physician Jaime Zipper discovered that copper could be an effective spermicide and developed the first copper IUD, TCu200. Improvements by Dr. Tatum led to the creation of the TCu380A (ParaGard), which is the current gold standard for copper IUDs.[16]

The hormonal IUD was also invented in the 1960s and 1970s. The first model, Progestasert, was conceived of by Dr. Antonio Scommengna and created by Dr. Tapani J.V. Luukkainen, but the device only lasted for one year of use.[17] Progestasert was manufactured until 2001.[18] The only commercial hormonal IUD still currently available, Mirena, was also developed by Dr. Luukkainen and released in 1976.[16]

Research

A lower-dose T-shaped IntraUterine System named Femilis is being developed by Contrel, a Belgian company. Contrel also manufactures the FibroPlant-LNG, a frameless IUS. FibroPlant is anchored to the fundus of the uterus as the GyneFix IUD is. Although a number of trials have shown positive results, FibroPlant is not yet commercially available.[19]

References

  1. ^ Winner B, Peipert JF, Zhao Q, et al. (May 2012), "Effectiveness of long-acting reversible contraception", N. Engl. J. Med. 366 (21): 1998–2007, doi:10.1056/NEJMoa1110855, PMID 22621627, http://www.nejm.org/doi/full/10.1056/NEJMoa1110855
  2. ^ World Health Organization (2002). "The intrauterine device (IUD)—worth singing about". Progress in Reproductive Health Research (60): 1–8. 
  3. ^ Treiman K, Liskin L, Kols A, Rinehart W (1995), "IUDs – an update" (PDF), Popul Rep B (6): 1–35, PMID 8724322, http://www.infoforhealth.org/pr/b6/b6.pdf, retrieved 2006-01-01
  4. ^ a b "Contraceptive coils (IUDs)". NetDoctor.co.uk. 2006. Retrieved 2006-07-05. 
  5. ^ French R, Van Vliet H, Cowan F, et al. (2004). "Hormonally impregnated intrauterine systems (IUSs) versus other forms of reversible contraceptives as effective methods of preventing pregnancy". In Sorhaindo, Annik M. Cochrane Database of Systematic Reviews (3): CD001776. doi:10.1002/14651858.CD001776.pub2. PMID 15266453. 
  6. ^ a b Grimes, DA, MD (2007), "Intrauterine Devices (IUDs)", in Hatcher, RA; Nelson, TJ; Guest, F; Kowal, D., Contraceptive Technology (19th ed.), New York: Ardent Media
  7. ^ "Mechanisms of the Contraceptive Action of Hormonal Methods and Intrauterine Devices (IUDs)". Family Health International. 2006. Retrieved 2006-07-05. 
  8. ^ Oritz ME, Croxatto HB (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. 
  9. ^ Kulier R, O'Brien PA, Helmerhorst FM, Usher-Patel M, D'Arcangues C (2007), "Copper containing, framed intra-uterine devices for contraception", Cochrane Database Syst Rev (4): CD005347, doi:10.102/14651858.CD005347, PMID 17943851
  10. ^ Schering (May 13, 2003). "Nova T380 Patient information leaflet (PIL)". Retrieved 2007-04-27. 
  11. ^ Cleland K, Zhu H, Goldstuck N, Cheng L, Trussell J (July 2012), "The efficacy of intrauterine devices for emergency contraception: a systematic review of 35 years of experience", Hum. Reprod. 27 (7): 1994–2000, doi:10.1093/humrep/des140, PMID 22570193, http://humrep.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=22570193
  12. ^ Belhadj H, Sivin I, Diaz S, et al. (September 1986), "Recovery of fertility after use of the levonorgestrel 20 mcg/d or Copper T 380 Ag intrauterine device", Contraception 34 (3): 261–7, doi:10.1016/0010-7824(86)90007-7, PMID 3098498
  13. ^ Li Y, Zhang SM, Chen F, et al. (December 2011). "[A multi-center randomized controlled trial of intrauterine device use in Chinese women]". Zhonghua Yi Xue Za Zhi (in Chinese) 91 (45): 3172–5. PMID 22333096. 
  14. ^ al.], [edited by] Steven G. Gabbe ... [et. Obstetrics : normal and problem pregnancies (6th ed. ed.). Philadelphia: Elsevier/Saunders. p. 528. ISBN 9781437719352. 
  15. ^ Takeshita, Chikako. The global biopolitics of the IUD : how science constructs contraceptive users and women's bodies. Cambridge, Mass.: MIT Press. p. 105. ISBN 9780262016582. 
  16. ^ a b c d e f g Thiery M (March 1997), "Pioneers of the intrauterine device", Eur J Contracept Reprod Health Care 2 (1): 15–23, doi:10.1080/13625189709049930, PMID 9678105, http://informahealthcare.com/doi/abs/10.1080/13625189709049930
  17. ^ a b Thiery M (June 2000), "Intrauterine contraception: from silver ring to intrauterine contraceptive implant", Eur. J. Obstet. Gynecol. Reprod. Biol. 90 (2): 145–52, PMID 10825633, http://linkinghub.elsevier.com/retrieve/pii/S0301211500002621
  18. ^ Smith (pseudonym), Sydney (March 8, 2003). "Contraceptive Concerns". medpundit: Commentary on medical news by a practicing physician. Retrieved 2006-07-16. 
  19. ^ "New Contraceptive Choices". Population Reports, INFO Project, Center for Communication Programs (The Johns Hopkins School of Public Health) M (19). April 2005. Retrieved 2006-07-14.  Chapter 9: Intrauterine Devices.