the uterus. after the pelvic exam, the vagina is held open with a speculum. a tenaculum is used to steady the cervix and uterus. uterine sounding may be used to measure the length and direction of the cervical canal and uterus in order to decrease the risk of uterine perforation. the iud is placed using a narrow tube, which is inserted through the cervix into the uterus. short monofilament plastic/nylon strings hang down from the uterus into the vagina. the clinician will trim the threads so that they only protrude 3 to 4 cm out of the cervix and remain in the upper vagina. the strings allow the patient or clinician to periodically check to ensure the iud is still in place and to enable easy removal of the device. the copper iud can be inserted at any time in a woman's menstrual cycle as long as the woman is not pregnant. an iud can also be inserted immediately postpartum and post-abortion as long as no infection has occurred. breastfeeding is not a contraindication for the use of the copper iud. the iud can be inserted in women with hiv or aids as it does not increase the risk of transmission. although previously not recommended for nulliparous women (women who have not had children), the iud is now recommended for most women who are past menarche (their first period), including adolescents. after the insertion is finished, normal activities such as sex, exercise, and swimming can be performed as soon as it feels comfortable. strenuous physical activity does not affect the position of the iud. types a variety of iuds many different types of copper iuds are currently manufactured worldwide, but availability varies by country. in the united states, only one type of copper iud is approved for use, while in the united kingdom, over ten varieties are available. one company, mona lisa n.v., offers generic versions of many existing iuds. iudtype width (mm) length (mm) copper (mm2)life (years)manufacturerdistinguishing characteristics gyneplus cu 380t-shaped 3805dispo.cont. multiload cu375u-shaped 20.5 353755multilan multiload cu250u-shaped 2503multilan multi-safe 375u-shaped 19.5 32.53755williams medical supplies multi-safe 375 short loopu-shaped 3755williams medical supplies load 375u-shaped 19.5 32.537557-med industrie nova-t 380t-shaped (plain) 32 323805bayer neo-safe t 380t-shaped (plain) 32 323805durbin neo-safe t 380 mini t-shaped (plain) 24 30 380 5 durbin ut 380t-shaped (plain) 32 323805laboratoire ccd ut 380 shortt-shaped (plain) 32 28.43805laboratoire ccd flexi-t 300t-shaped (plain) 23 293005prosan flexi-t + 300t-shaped (plain) 28 323005prosanwider arms than flexi-t 300 t-safe cu 380at-shaped (banded) 31.8 35.83808durbin flexi-t + 380t-shaped (banded) 28 323805prosan tt 380 slimlinet-shaped (banded) 31.8 35.8380107-med industrie tt 380 minit-shaped (banded) 23.2 29.538057-med industrie paragardt-shaped (banded) 32 3638010duramedonly copper iud currently approved by the u.s. fda gynefix 330 (standard)frameless 2.2 303305 or 10contrelonly frameless iud brand available gynefix 200 (mini)frameless 2005contrelonly frameless iud brand available iub scu300a/bspherical (3d) 3005oconnitinol alloy cored frame. brand name is ballerine. smb tcu 380at-shaped (banded) 32 36 38010smb corpwho unfpa prequalified iud manufacturer protect tcu 380a t-shaped (banded) 380 12 smb corp who unfpa prequalified iud manufacturer protect multi-arm cu 375 standard u-shaped 375 5 smb corp who unfpa prequalified iud manufacturer protect multi-arm cu 375 short u-shaped 375 5 smb corp who unfpa prequalified iud manufacturer frameless iuds the frameless iud eliminates the use of the frame that gives conventional iuds their signature t-shape. this change in design was made to reduce discomfort and expulsion associated with prior iuds; without a solid frame, the frameless iud should mold to the shape of the uterus. it may reduce expulsion and discontinuation rates compared to framed copper iuds. gynefix is the only frameless iud brand currently available. it consists of hollow copper tubes on a polypropylene thread. it is inserted through the cervix with a special applicator that sutures the thread to the fundus (top) of the uterus; the thread is then cut with a tail hanging outside of the cervix, similar to frame iuds. when this tail is pulled, the suture comes undone and the device can be removed. this requires more force than removing a t-shaped iud and results in comparable discomfort during removal. gynefix is not approved for use in the united states. mechanism of action a diagram showing a copper iud in place in the uterus. the copper iud's primary mechanism of action is to prevent fertilization. copper acts as a spermicide within the uterus. the presence of copper increases the levels of copper ions, prostaglandins, and white blood cells within the uterine and tubal fluids. although not a primary mechanism of action, some experts in human reproduction believe there is sufficient evidence to suggest that iuds with copper can disrupt implantation, especially when used for emergency contraception. despite this, there has been no definitive evidence that iud users have higher rates of embryonic loss than women not using contraception. therefore, the copper iud is considered to be a true contraceptive and not an abortifacient. usage globally, the iud is the most widely used method of reversible birth control. the most recent data indicates that there are 169 million iud users around the world. this includes both the nonhormonal and hormonal iuds. iuds are most popular in asia, where the prevalence is almost 30%. in africa and europe, the prevalence is around 20%. as of 2009, levels of iud use in the united states are estimated to be 5.5%. data in the united states does not distinguish between hormonal and non-hormonal iuds. in europe, copper iud prevalence ranges from under 5% in the united kingdom to over 10% in denmark in 2006. history according to popular legend, arab traders inserted small stones into the uteruses of their camels to prevent pregnancy during long desert treks. the story was originally a tall tale to entertain delegates at a scientific conference on family planning; although it was later repeated as truth, it has no known historical basis. 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. because they occupied both the vagina and the uterus, this type of stem pessary was also known as an intrauterine device. the use of intrauterine devices was associated with high rates of infection; for this reason, they 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 of germany published a report on an iud made of silk sutures. he had found a 3% pregnancy rate among 1,100 women using his ring. in 1930, gräfenberg reported a lower pregnancy rate of 1.6% among 600 women using an improved ring wrapped in silver wire. unbeknownst to 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 gräfenberg's 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 were further stifled by world war ii politics: contraception was forbidden in both nazi germany and axis-allied japan. the allies did not learn of the work by gräfenberg and ota until well after the war ended. the first plastic iud, the margulies coil or margulies 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 modern colloquialism "coil" is based on the coil-shaped design of early iuds. the lippes loop, a slightly smaller device with a monofilament tail, was introduced in 1962 and gained in popularity over the margulies device. the stainless steel single-ring iud was developed in the 1970s 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). howard tatum, in the us, conceived the plastic t-shaped iud in 1968. shortly thereafter jaime zipper, in chile, introduced the idea of adding copper to the devices to improve their contraceptive effectiveness. it was found that copper-containing devices could be made in smaller sizes without compromising effectiveness, resulting in fewer side effects such as pain and bleeding. t-shaped devices had lower rates of expulsion due to their greater similarity to the shape of the uterus. the poorly designed dalkon shield plastic iud (which had a multifilament tail) was manufactured by the a. h. robins company and sold by robins in the united states for three and a half years from january 1971 through june 1974, before sales were suspended by robins on june 28, 1974, at the request of the fda because of safety concerns following reports of 110 septic spontaneous abortions in women with the dalkon shield in place, seven of whom had died. robins stopped international sales of the dalkon shield in april 1975. tatum developed many different models of the copper iud. he created the tcu220 c, which had copper collars as opposed to a copper filament, which prevented metal loss and increased the lifespan of the device. 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 achieved effectiveness rates of greater than 99%. the last model tatum developed was the tcu380a, the model that is most recommended today. in addition to t-shaped iuds, there are also u-shaped iuds (such as the multiload) and 7-shaped gravigard copper 7 (with a mini version for nulliparous women introduced in the 1980s). more recently, a frameless iud called gynefix was introduced. brands the paragard t-380a is an iud with copper, manufactured and marketed in the united states by the cooper companies. it is the only copper-containing intrauterine device approved for use in the u.s. (three hormonal uterine devices, mirena, skyla and liletta are also approved). the paragard consists of a t-shaped polyethylene frame wound with copper wire, along with two monofilament threads to aid in the removal of the iud. the paragard t 380a was developed in the 1970s by the population council and finishing enterprises inc. (fei). the population council's paragard new drug application (nda) was approved by the u.s. food and drug administration (fda) and fei began manufacturing it for distribution outside the united states in 1984. gynopharma (originally gynomed) began marketing it in the u.s. in may 1988. on august 2, 1995, ortho-mcneil acquired gynopharma and began marketing paragard in the u.s. on january 1, 2004, fei women's health acquired the patent from the population council and u.s. marketing rights from ortho-mcneil. on november 10, 2005, duramed pharmaceuticals, a subsidiary of barr pharmaceuticals, acquired fei women's health and paragard. on july 18, 2008, it was announced that teva pharmaceutical industries ltd. would acquire barr pharmaceuticals. on november 1, 2017, the cooper companies acquired paragard from teva pharmaceutical industries for approximately $1.1 billion. the original fda approval of paragard in 1984 was for 4 years continuous use, this was later extended to 6 years in 1989, then 8 years in 1991, then 10 years in 1994. (atc code g02ba02 (who))