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Intrauterine device

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An intrauterine device (intra meaning within, and uterine meaning of the uterus) is a birth control device also known as an IUD or a coil (this colloquialism is based on the coil-shaped design of early IUDs). It is a device placed in the uterus and is the world's most widely used method of reversible birth control. The device has to be fitted inside or removed from the uterus by a doctor or qualified medical practitioner. It remains in place the entire time contraception is desired. Depending on the type, a single IUD may be used for 5 to 10 years.

Contents

Types of IUDs

Availability of IUDs varies widely by country. Only one brand (Paragard T 380A), for example, is available in the United States, while seven brands (Flexi-T 300, GyneFix - also called FlexiGard 330 or CuFix PP330, Multi-Safe 375, Multi-Load Cu 375, Neo-Safe T380, Nova T 380, T-Safe 380A) are available in Great Britain. There are also hormonal devices that are placed in the uterus (IntraUterine System). Most types of IUDs have a plastic T-shaped frame that is wrapped with copper and/or has copper bands. Some IUDs, such as the Nova T 380, also contain a small amount of silver. The arms of the frame hold the IUD in place near the top of the uterus. The GyneFix does not have a T-shape, but rather is a loop that holds several copper tubes. The GyneFix is held in place by a suture to the fundus of the uterus. All copper-containing IUDs have a number as part of their name. This is the surface area of copper (in square millimeters) the IUD provides.

Effectiveness and mechanism of contraception

All second-generation copper-T IUDs have failure rates of less than 1% per year, and cumulative 10-year failure rates of 2-6%. [Chapter 2.3: Effectiveness]. The frameless GyneFix also has a failure rate of less than 1% per year. Worldwide, older IUD models with lower effectiveness rates are no longer produced.IUDs—An Update. [Chapter 1: Background]. The presence of a device in the uterus prompts the release of leukocytes and prostaglandins by the endometrium. These substances are hostile to both sperm and eggs; the presence of copper increases this spermicidal effect. Although the only experimentally demonstrated effect is spermicidal/ovicidal, it is possible the IUD may rarely prevent the development of embryos. IUDs can not protect from STDs, and if an infection is caught while using an IUD it may be more likely to spread to the uterus.

Contraindications

IUDs are not usually recommended for:IUDs—An Update. [Sidebar: WHO Scientific Group Updates Eligibility Guidelines for Copper IUDs].
  • Women at risk for certain sexually transmitted diseases (STDs) that can cause pelvic inflammatory disease (PID), or with or at risk for HIV. Presence of an IUD increases the risk of an STD progressing to PID, and increases the risk of a PID causing infertility.
  • Women who are anemic and experience heavy menstrual bleeding.
  • Women between 48 hours and four weeks postpartum. Perforation of the uterus is more likely to occur during insertion when the women is more than 48 hours but less than four weeks postpartum.IUDs—An Update. [Chapter 3.3: Postpartum Insertion].
  • Women with benign trophoblast disease (molar pregnancy).
IUDs may not be inserted in:
  • Women who are pregnant.
  • Women with an active STD, or who have had PID within the past three months.
  • Women who have sepsis (infection) following childbirth or abortion.
  • Women with certain uterine abnormalities.
  • Women with pelvic tuberculosis.
  • Women with cervical, endometrial, or ovarian cancer awaiting treatment.
  • Women with malignant trophoblast disease.
While nulliparous women are somewhat more likely to have side effects, this is not a contraindication for IUD use. The GyneFix is more recommended for nulliparous women, as it appears to be better tolerated in that population.

Side effects and complications

IUDs may make menstrual periods heavier and/or more painful, especially for the first few months after they are inserted. Because it is smaller, the GyneFix is less likely to affect periods than T-shaped devices.

Insertion of the IUD may introduce bacteria into the uterus. It is very important that the provider use proper infection-prevention techniques during insertion.IUDs—An Update. [Sidebar: Infection Prevention for IUD Insertion and Removal]. Antibiotics should be given before insertion to women at high risk for endocarditis (inflammation of the membrane lining the heart), but should not be used routinely.IUDs—An Update. [Sidebar: Procedures for Providing IUDs]. Complications include expulsion and uterine perforation. Uterine perforation is generally caused by an inexperienced provider. Expulsion is more common in younger women, women who have not had children, and when an IUD is inserted immediately after childbirth or abortion.

The risk of ectopic pregnancy to a woman using an IUD is lower than the risk of ectopic pregnancy to a woman using no form of birth control. However, of pregnancies that do occur during IUD use, a higher than expected percentage is ectopic.

Use as emergency contraception

Intrauterine devices can be used as emergency contraception to prevent pregnancy up to 5 days after unprotected sexual intercourse, or sexual intercourse during which the primary contraception is believed to have failed (e.g. a condom was used, but it broke). Insertion of a copper-T IUD as emergency contraception is more than 99% effective, making it more effective than emergency contraceptive pills (ECP or 'morning-after pill').

IUDs may also be used where ECPs are less appropriate:

  • ECP are contraindicated in those with severe liver disease or the very rare condition of porphyria.
  • ECP are currently licensed for only 3 days (72 hours) after coitus
  • ECP will be ineffective if currently suffering from diarrhea or vomiting
  • The effectiveness of ECP may be reduced by the herbal preparation St John's wort and enzyme-inducing drugs (e.g. antiepileptics or rifampicin).

Popularity

The ParaGard T 380A was approved by the U.S. Food and Drug Administration (FDA) in 1984 and became available for use in 1988. It is still the only IUD approved for use in the U.S., and is used by 1.3% of women of reproductive age.[National Survey of Family Growth] Use of Contraception and Use of Family Planning Services in the United States: 1982-2002. Advance Data No. 350 Usage in other countries has been determined by surveys of married women of reproductive age. In this population, IUD use ranges from 5% in Belgium, to 18% in Scandinavia, 30% in Russia and China, and 40% in Kazakstan.IUDs—An Update. [Worldwide Use - Developed Countries]. [Table 2: Worldwide Use of IUDs].

Hormonal uterine devices

Photo of LNG IUS
Enlarge
Photo of LNG IUS

Although many organizations refer to all types of uterine devices as IUDs,[IUDs - An Update] others use the term IUD only for inert or copper-containing devices, and consider the hormonal uterine devices to be a seperate method of contraception termed IntraUterine System or IUS. Progestasert was the first hormonal uterine device, developed in 1976IUDs—An Update. [Chapter 2: Types of IUDs]. and manufactured until 2001. It contained bioidentical progesterone (not a progestin) that was released at a rate of 65 micrograms per day. In most countries it was replaced annually, though it was approved for 18 months of use in France. It had a failure rate of 2% per year. The LNG-20 IUS - marketed as Mirena by Schering Health - was introduced in Finland in 1990, but not approved by the U.S. Food and Drug Administration until 2000. It initially releases 20 micrograms of levonorgestral (a progestagen) per day and may be used for five years.

Contrel, the Belgian company that developed the GyneFix IUD, is developing a second-generation T-frame IUS named Femilis. Femilis would come in a smaller size (Femilis Slim) for nulliparous women. It would be inserted without a plunger, and it is hoped its performance would be less dependent on the experience of the health care professional.

Several trials with positive results have been done on a frameless IUS called FibroPlant-LNG (also from Contrel). FibroPlant is anchored to the fundus of the uterus as GyneFix is, initially releases 14 micrograms of levonorgestral per day, and may be used for at least three years. As of 2005, it was not commercially available. [Chapter 9: Intrauterine Devices].

History

Presenters at a family planning conference told a tale of Arab traders inserting small stones into the uteruses of their camels to prevent pregnancy. Although the story has been repeated as truth, it has no basis in history and was meant only for entertainment purposes., which cites:
 Precursors to IUDs were first marketed in 1902. Developed from stem pessaries (where the stem held the pessary in place over the cervix), the 'stem' on these devices actually extended into the uterus itself. Also known as interuterine devices (because they occupied both the vagina and the uterus), they had high rates of infection and were condemned by the medical community. The first intrauterine device (contained entirely in the uterus) was described in a German publication in 1909, although the author appears to have never marketed his product. In 1929, Ernst Gräfenberg published a report on an IUD made of silk suture. He had found a 3% pregnancy rate among 1,100 women using his ring. In 1930, Dr. Gräfenberg reported a lower pregnancy rate of 1.6% among 600 women using an improved ring wrapped in silver wire. Unbeknownst to Dr. Gräfenberg, the silver wire was contaminated with 26% copper. Copper's role in increasing IUD efficacy would not be recognized until nearly 40 years later.

In 1934, Japanese physician Tenrei Ota developed a variation of the Gräfenberg ring that contained a supportive structure in the center. The addition of this central disc lowered the IUD's expulsion rate. These devices still had high rates of infection, and their use and development was further stifled by World War II politics: contraception was forbidden in both Nazi Germany and Axis-allied Japan. The Western world did not learn of the work by Gräfenberg and Ota until well after the war ended. The first plastic IUD, the Marguiles Coil or Marguiles Spiral, was introduced in 1958. This device was somewhat large, causing discomfort to a large proportion of women users, and had a hard plastic tail, causing discomfort to their male partners. The Lippes Loop, a slightly smaller device with a monofilament tail, was introduced in 1962 and gained in popularity over the Marguiles device. The stainless steel single-ring IUD was developed in the 1970s (Has pictures of various IUD designs.) and widely used in China because of low manufacturing costs. The Chinese government banned production of steel IUDs in 1993 due to high failure rates (up to 10% per year). Dr Howard Tatum, in the USA, conceived the plastic T-shaped IUD in 1968. Shortly thereafter Dr Jaime Zipper, in Chile, introduced the idea of adding copper to the devices to improve their contraceptive effectiveness. (Has pictures of many IUD designs, both historic and modern.) It was found that copper-containing devices could be made in smaller sizes without compromising effectivesness, resulting in fewer side effects such as pain and bleeding.IUDs—An Update. [Chapter 1: Background]. T-shaped devices had lower rates of expulsion due to their greater similarity to the shape of the uterus. The Dalkon Shield (which had a multi-filiment string) was introduced in the United States in 1970. It was banned after being linked to a large number of infections, septic abortions, infertility, and several deaths (it was thought the thick woven string hosted bacteria, which could spread to cause reproductive tract infections). The negative publicity of the Dalkon Shield generated negative opinions of all IUDs, and by 1986 the only uterine contraceptive remaining on the U.S. market was the Progestasert, a hormonal device that had been introduced in 1976.IUDs—An Update. [Chapter 1: US Situation]. [Chapter 2: Types of IUDs] Second-generation copper-T IUDs were also introduced in the 1970s. These devices had higher surface areas of copper, and for the first time consistently acheived effectiveness rates of greater than 99%. Worldwide today, with the exception of the new GyneFix, this is the only type of IUD available.

See also

External links

References


 

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