Clinical Characteristics of IUDs
Most women who use IUDs are very satisfied with the method (156, 198). Many women prefer the IUD because it provides very effective, long-term and yet quickly reversible protection against pregnancy. Also, the IUD is convenient. It requires very little action from the woman once it is in place. On average, women use IUDs longer than other reversible contraceptive methods (3, 18).
With copper-bearing IUDs, increased bleeding is common and the primary medical reason that women stop using IUDs (244). Other side effects and complications with IUD use, including expulsion and perforation of the uterus, are uncommon. Researchers continue to develop and test new IUDs that promise to reduce expulsion rates and side effects and that simplify insertion procedures. (See Population Reports,“New Contraceptive Choices”, Series M, Number 19, April 2005.)
Proper IUD insertion minimizes the risks of many complications with IUD use such as expulsion and perforation. When service delivery is organized so that clients are referred to a core group of well-trained providers, these providers will see enough IUD clients to maintain their insertion skills and help ensure a high quality of care (see 'Feature: Good Counseling Increases Client Satisfaction'). These providers also will have the skills necessary to manage any problems that IUD users may encounter. (See Web Box ) for a preview of consensus-based guidance on managing problems with IUD use from the forthcoming update of the Essentials of Contraceptive Technology handbook).
One of the Most Effective Methods
|
Effectiveness of IUDs is similar to that of female sterilization.
|
In a large international multicenter study sponsored by WHO, only about 4 women in every 1,000 using the TCu-380A became pregnant in the first year of use (249). This amounts to 0.4%. Earlier studies reported similar pregnancy rates—3 to 8 women per 1,000 became pregnant in the first year of use (0.3% to 0.8%) (214, 216). These rates are similar to those for female sterilization, another of the most effective family planning methods.
The levonorgestrel-releasing IUD (LNG-IUD) also has very low first-year pregnancy rates. Between 1 and 3 women per 1,000 become pregnant in the first year of use (0.1% to 0.3%) (125, 214). Preliminary results from a large WHO international study comparing the TCu-380A and the LNG-IUD suggest that the LNG-IUD is more effective (267). After a total of six years of use, 5 women of every 1,000 using the LNG-IUD became pregnant compared with 20 per 1,000 using the TCu-380A.
Copper-Bearing IUDs Increase Bleeding
Copper-bearing IUDs increase blood flow volumes by 20% to 50% above levels before IUD insertion (244). Increased menstrual bleeding, often with pain, is the problem that women most often report while using copper-bearing IUDs. Many women who have these complaints keep their IUDs nonetheless (52). Overall rates of removal because of bleeding and/or pain at 12 months of use range from 1 to 17 per 100 women in major clinical trials of the TCu-380A and other copper-bearing IUDs (51–54, 165, 177, 214, 249).
The increased bleeding could decrease blood iron levels. Some studies find no change in blood iron levels compared with levels before insertion of a copper-bearing IUD (115, 182). Other studies have found lower average blood iron levels in IUD users than before IUD insertion or when compared with levels in women not using contraception (44, 56, 72, 87, 238). Decreases in blood iron levels measured about two to four grams per liter after 12 months of IUD use. While the average change is small, these decreases could be enough to lead to a diagnosis of clinical anemia among women who already have relatively low blood iron levels before IUD insertion (87, 184) (See Web Box ). WHO considers normal blood iron levels in nonpregnant women to be above 120 grams per liter (263).
Hormonal IUDs Decrease Bleeding
At first, during the first three months of use and sometimes longer, LNG-IUD users are likely to have markedly more days of vaginal bleeding and spotting than before IUD use (7, 88, 235). The amount and duration of blood flow gradually decreases, however, because the continuous dose of progestin keeps the lining of the uterus thin. In fact, 20% to 35% of LNG-IUD users have no vaginal bleeding at all by the end of the first year of use (7, 38, 69, 127, 161, 235). Even more users experience only light bleeding (188, 217, 235). The decrease in or absence of bleeding is not harmful and does not affect a woman’s ability to produce eggs or other aspects of fertility once the IUD is removed (155, 275, 276). In fact, the LNG-IUD has several therapeutic applications because it reduces bleeding (see Table 1).
Counseling women before LNG-IUD insertion that the device may stop menstrual bleeding—and that this is harmless— is key to successful LNG-IUD use. Women who receive such counseling are more satisfied with the method than less informed women (9), and they are more likely to continue using the method (7, 188). In fact, many women see the absence of bleeding as an advantage of the LNG-IUD and a reason to continue using it (188). Still, some women will not accept the possible lack of menstrual bleeding. For these women, providers can propose the copper-bearing IUD or other contraceptive methods.
Expulsion Uncommon
|
Careful insertion of the IUD as high as possible in the uterus helps avoid its expulsion. Women who expel their devices risk pregnancy. From JHPIEGO, IUD guidelines for family planning service programs: A problem-solving reference manual
|
After IUD insertion uterine contractions can push the device downward, causing expulsion from the uterus. Correct insertion, with the IUD placed up to the top of the uterus, may reduce the chances of expulsion. Recent studies show, however, that T-shaped IUDs inserted low in the uterus tend to move upward on their own within two to three months after insertion (285, 294).
Expulsion rates vary from 2 to 8 per 100 women in the first year of use (160, 189, 247, 274). Most expulsions occur in the first year and especially during the first three months after insertion (8, 247, 274). About one expulsion in every five goes unnoticed at the time (142). Women who expel their devices are at risk of pregnancy, especially if they do not notice the expulsion. Expulsion usually is not otherwise harmful.
Expulsion is more likely in such circumstances as:
- Young age at insertion (under 20 or 25 years old) (126, 183, 215, 259, 281),
- Insertion early in the menstrual cycle (259),
- Immediate postpartum insertion (76, 257, 278), and
- Insertion immediately after second-trimester abortion (75).
- Some studies have found a higher rate of expulsion among women who have no children (121, 126, 164, 215, 259).
The additional risk of expulsion is not sufficient to deny IUDs to women in any of these circumstances. Specifically, WHO advises that women under age 20 and women who have had no children generally can still use IUDs, because the advantages of the IUD outweigh the risk of expulsion (268).
Perforation Rare
Perforation of the uterus can occur during IUD insertion, when the IUD or a gynecological instrument pierces the uterine muscle wall. Careful insertion technique can avoid perforations. In large clinical trials uterine perforation is rare —fewer than 2 per 1,000 insertions (14, 24, 247, 249, 274). Most perforations are recognized at insertion, and the IUD can be removed at once without causing any serious problems (see Web Box). Some perforations go unnoticed and can lead to adhesions (fibrous bands of scar tissue that form between two surfaces inside the body). Usually, the adhesions do not cause any problems, but a few cases of bowel obstruction have been reported (1, 74, 157, 173).
Pregnancy Rare but Serious
The IUD is a very effective contraceptive. If pregnancy does take place with an IUD in place, however, potentially severe complications can occur such as miscarriage (244). In various reports 15% to 60% of uterine pregnancies ended in miscarriage if the IUD was not removed (40, 67, 112, 140, 223). Removing the IUD reduces this risk of miscarriage to about the same level of risk faced by other women, although the removal process itself entails a small risk of miscarriage (244) (see Web Box). Studies have found that septic (infected) second-trimester miscarriage—a rare life-threatening condition— was more common among women who left their IUDs in place than among women not using IUDs at conception (244).
IUDs Reduce Risk of Ectopic Pregnancy
Because any pregnancy among IUD users is rare, ectopic pregnancy (pregnancy outside the uterus) in IUD users is even rarer. Data from 42 clinical trials report an ectopic pregnancy rate of 2 per 1,000 women over 10 years’ use of the TCu-380A (or 0.2%) (212). Various studies have estimated that IUDs reduce ectopic pregnancy rates to 10% to 50% of the level among women not using contraception (146, 221, 271, 277).
The IUD helps to prevent ectopic pregnancy, but not as well as it prevents intrauterine pregnancy. In the rare event that an IUD user becomes pregnant, the pregnancy is much more likely to be ectopic than a pregnancy in a woman not using an IUD (68, 146, 277). Older women face greater risk that a pregnancy will be ectopic, as is true among women not using IUDs (212). Health care providers should be particularly alert for the possibility that a pregnancy in any IUD user is ectopic. In users of copper-bearing IUDs, an estimated 1 in every 13 to 16 pregnancies is ectopic (6% to 8%) (68, 136). The likelihood of ectopic pregnancy in the general population varies widely from country to country. In the US, according to the most recent data available, in 1992 some 2% of all pregnancies were ectopic (27).
*******
While misinformation about the safety and perceived programmatic challenges have limited IUD use in many countries, some family planning programs are now taking steps to correct these misperceptions and create or revive interest in the method. The IUD can be a good choice for women who want a highly effective and convenient method that is long-lasting but also quickly reversible.
|
Order this report
Download PDF
E-mail this page 
See more Population Reports