Intrauterine contraceptive device (IUD)
- What is an IUD?
- History of IUDs
- What types of IUDs are available?
- How do IUDs work?
- How popular are IUDs?
- How effective are IUDs?
- Who can use an IUD?
- When can an IUD be inserted?
- How is an IUD fitted?
- What to do after your IUD is inserted?
- Removal of an IUD
- Advantages of IUDs
- Disadvantages of IUDs
- Risks associated with IUDs
What is an IUD?
An intrauterine device (IUD) is a small T shaped plastic device that is placed inside the uterus to prevent pregnancy. It is a long lasting and easily reversible method of contraception and is currently the second most commonly used method worldwide following sterilisation. The intrauterine device comes in two types, a copper IUD which is made of plastic and copper (Multiload 375 or Copper T 380), and a hormone releasing IUD (Mirena) which is made of plastic and contains levonorgestrel, a synthetic progesterone, that is released slowly into the uterus.
History of IUDs
It is believed that the concept of IUDs first arose from the practice of putting stones in the uterus of camels in order to prevent pregnancies during long journeys. The first human intrauterine device was introduced in the 1960s and was made of inert plastic. In the late 1960s it was discovered that adding copper to the plastic IUD made it a more effective contraceptive while also reducing the risk of bleeding. Thus, later versions increased the amount of copper in the devices as this helped to raise its contraceptive efficiency. These early IUDs required replacement every 2-3 years.
IUD popularity peaked in the late 1970s as women became concerned about the hormonal effects of oral contraceptives. However one particular IUD introduced in the 70s known as the Dalkon shield resulted in numerous infections of the uterus giving IUDs a bad reputation which resulted in a large decline in their use. These concerns still prevail today particularly in the western world where IUD use is the lowest. Therefore it is important be aware of the advantages and disadvantages of modern IUDs.
Overall, the IUD is one of the safest, and most tolerated methods of birth control available and its low failure rate (1-3%) makes it one the highest contraceptive efficiency of all contraceptive methods.
What types of IUDs are available?
There are essentially two types of IUDsavailable; the copper IUD one and the newer hormonal levonorgestral releasing IUD (LNG, IUS or Mirena).
The copper IUD consists of a polyethylene plastic frame with copper wire coiled around the stem and arms. It also has a plastic monofilament thread attached at the end of the stem which hangs from the cervix into the vagina. This thread aims to assist in the placement and removal of the IUD. The two main brands available in Australia are the copper T 380 and the multiload 375. The copper IUD has been approved for use for up to 10 years and can be effective for up to 12 years.
It can be inserted at any time during the menstrual cycle as long as pregnancy has been excluded. Further, it can be inserted immediately after abortion and immediately postpartum (within 48 hours of giving birth). The advantage of the copper IUD is that it is hormone-free providing a suitable option for women who experience problems with hormonal methods. Another role of the copper IUD is as an emergency contraceptive. It can prevent up to 99% of pregnancies when inserted within 5 days of unprotected sex.
Hormone releasing IUD/ Levonorgestrel IUD (LNG-IUD)
The more recently developed hormone releasing IUD has been available in the US since 2000 but was widely used in Europe since 1990. In Australia it was listed on the PBS for use as a contraceptive in 2003. This IUD is also made of plastic but contains within it a progestogen hormone called levonorgestrel. It is a 32mm long t shaped device with a monofilament thread attached to a loop on the bottom of the stem. Instead of copper it contains 52mg of levonorgestrel which is released at a rate of 20 micrograms per day. This IUD has more restrictions in its use and when it can be inserted and must be replaced after 5 years.
The hormone releasing IUD (Mirena) also has many other uses apart from its role as a contraceptive. This IUD is also useful alternative to hysterectomy for the treatment of menorrhagia, dysfunctional uterine bleeding and leiomyomas however, it cannot be used for emergency contraception.
How do IUDs work?
Both types of IUDs work by preventing sperm from fertilising the ovum (egg). This is achieved by inhibition of sperm and/or ovum motility or viability. The early IUDs which were made of inert plastic worked by inducing a foreign body response in the uterus which resulted in the body’s own immune system destroying the sperm. These early devices were characterized by a significant increase in menstrual blood loss.
Copper IUDs act by impairing sperm function and movement through the uterus, as copper is toxic to sperm. They do this by instigating a reaction which induces cellular and humoural inflammatory response to the presence of the copper within the cervical mucous, uterine cavity and fallopian tube. The copper and the inflammatory response are both spermicidal.They also cause changes in the lining of the uterus which prevents an egg attaching to the endometrium if it does happens to get fertilised. It is this irritation that leads to the increased bleeding and heavier periods.The more modern copper IUDs are associated with less blood loss and are also more efficacious.
Since the earlier devices, IUDs have become smaller, have incorporated larger amounts of copper and are more effective and acceptable to users.Depending on the type of copper IUD used, they generally last for about 5-10 years, although effectiveness up to 12 years has also been found. One of the main advantages of copper IUDs is that they can be removed any time and once removed, the likelihood of becoming pregnant returns to normal immediately.
The hormone releasing IUD (Mirena) works by releasing a progestogen hormone that causes thickening of the mucous of the cervix thereby inhibiting penetration of sperm. It also makes the lining of the uterus thinner and hence less likely for a pregnancy to occur. In contrast to the copper IUD, most women find that with the hormone releasing IUD their periods become shorter, lighter and less painful. This device lasts for 5 years and can also be removed quickly and easily. Hormonal side effects are rarely experienced because the amounts of progestogen released is so small and is predominantly localized to the uterus that very minimal amounts enter the blood stream. This IUD can also be used to treat painful or heavy periods and as an alternative hormone replacement therapy (HRT) treatment instead of progestogen tablets.
How popular are IUDs?
IUDs are currently the second most popular method of contraception around the world following sterilisation with 13% of women using IUDs.However, there is a great disparity between its use in developed versus developing countries. In western countries IUDs are used on average by 7.6% of women while in developing countries it is almost double at 15%.China is one of the largest users of IUDs with over a third of women using them as form of contraception.Scandanavian countries such as Finland and Norway are the highest users of IUDs among the developed nations.
Although they are highly effective and safe, IUDs are still not incorporated into many family planning programs.In western countries this is due to the past history and misconceptions IUDS have of causing pelvic infection and other complications such as bleeding, pain and ecotopic pregnancy. In Australia only 1.5% of women use IUDs as a method of birth control. The IUD is highly underutilized primarily due to the misconceptions of the risks associated with it such as infertility and pelvic infections and that the earlier copper IUDs caused longer and more painful and heavy periods.This adverse publicity has given IUDs a bad reputation and explains their limited use.
How effective are IUDs?
IUDs are one of the most effective forms of contraception. They are more than 99% effective at preventing pregnancy with less than one pregnancy occurring per 100 women using an IUD in the first year. Over ten years use this increases slightly to about 2 pregnancies for every 100 women. The Tcu-380A is effective for 12 years.Copper IUDs are effective for 10 years while Mirena is effective for 5 years. Once the IUD is removed, fertility returns to normal immediately.
Who can use an IUD?
The IUD is an effective, safe and reliable method of contraception. To determine whether an IUD is suitable for you, your doctor will take a detailed medical history.It is an ideal method of contraception for women who have already had a child and is not recommended for women who have never given birth because their smaller uterus makes the IUD difficult to insert and they also have high rates of expulsion.
IUD use is not suitable for women who:
- Have a pelvic infection;
- May be pregnant;
- Have abnormal vaginal bleeding for which the cause has not been found;
- Have a high risk of acquiring a sexually transmitted infection (STI);
- Cancer of uterus, cervix or endometrium;
- Have an allergy to copper (applies to copper IUDs only);
- Have Wilson’s disease (applies to copper IUD only);
- Copper IUDs are not suitable for women who have very painful, heavy or prolonged periods or who have iron deficiency anaemia.
May not be suitable for women who:
- Have never had a child;
- Have more than one sexual partner or a partner who has other partners;
- Have a bleeding disorder;
- Vavular heart disease;
- Have a uterine abnormality such as fibroids;
- Painful or heavy periods;
- Unexplained vaginal bleeding;
- Moderate to severe anaemia;
- Previous ectopic pregnancy;
- Recent history of Pelvic Inflammatory Disease (PID);
- Uterine or cervix abnormality;
- Difficulties with vaginal examination and procedures.
When can an IUD be inserted?
Intrauterine devices can be inserted any time as long as pregnancy can be excluded, and once in place the IUD is effective immediately.The copper IUD can be fitted between the first day of period and ovulation. The LNG-IUD (Mirena) can be inserted between day 1 (first day of menstrual bleeding) to day 7 of the menstrual cycle or at other times provided there is no possibility of pregnancy.
It is recommended that women be screened for genital infections prior to insertion of IUD.
An IUD can also be inserted during a termination of pregnancy as long as no there is no evidence of infection. As an emergency contraceptive the copper IUD must be fitted within 120 hours following unprotected sex or within 5 days of the earliest date of ovulation (day 19 in women with regular 28 day cycles).
Copper IUDs can be inserted up to 48 hours post partum while the hormonal IUD can also be inserted safely in women four weeks post partum without any effect on breastfeeding.
How is an IUD fitted?
Insertion of IUDs inside the uterus is carried out as a minor surgical procedure performed under local anaesthetic. A doctor or nurse will conduct an internal exmination to determine size and position of the uterus. A speculum is put into your vagina so that the doctor can see the cervix. After measuring the length of the uterus with a small metal rod the device is inserted. During insertion you may experience dizziness or cramping similar to period pain. It is recommended that women take some pain medication such as neurofen about an hour before insertion. Women who have not given birth before may find the IUD insertion more uncomfortable than those who have.
What to do after your IUD is inserted?
After an IUD is fitted into the uterus a women should avoid inserting anything into the vagina for 48 hours to reduce the risk of infection. That is, no tampons, intercourse, swimming or baths for two days after insertion.
You will need to see a doctor for check up after the next period then once every two years. In a very small percentage of women, the IUD may be expelled by the uterus. This usually occurs in the first month after insertion and is more common in women who have never given birth.
Always check the thread of your IUD as this can tell you if it is still in place. Pregnancies usually occur when using IUDs do not notice it has been expelled.
Removal of an IUD
Women should never try to remove the IUD themselves as this can cause serious damage. A doctor can remove an IUD by pulling the string ends at a certain angle. This causes the IUD arms to fold up and the IUD to slide out through the cervix.
Advantages of IUDs
- The IUD provides a long lasting, highly effective contraception and is easily reversible;
- Although it has a higher initial cost, there are no ongoing costs involved following insertion making it the most cost-effective contraceptive in the long term;
- Rapidly reversible making it an ideal method for women who want long term birth control and want to retain fertility;
- Very effective and safe;
- It has no effect on breast milk or breast feeding;
- Does not interfere with sexual intercourse;
- Does not interfere with any medication;
- Once it is in place it can be forgotten and so there is no need to rely on the memory of the user;
- Requires minimal input by user and therefore minimising user error;
- Does not interfere with normal hormonal cycles;
- Suitable for women who are unable to take the pill;
- Is as effective as sterilisation, injectable contraception and sub-dermal implant;
- 1-2% failure rate;
- Hormone releasing IUD (Mirena) is suitable for women who have heavy menstrual bleeding;
- Private and discreet method;
- There is some evidence to suggest that the copper IUD may reduce the risk of endometrial cancer. This may also be the case for levonorgestrel IUD;
- The hormonal IUD can also be used as an alternative to surgical or oral hormonal treatments for women with heavy menstrual bleeding and by menopausal women taking estrogen who cannot tolerate other forms of progestogen.
Disadvantages of IUDs
- Must be inserted and removed by a trained medical professional;
- They can produce longer, heavier and sometimes painful menstrual period especially during the first 3-6 months of use. Spotting and light bleeding in between periods may also be experienced, however this is normal and reduces over time;
- Unpredictable bleeding also common with the levonorgestrel system which can last about 4 months of use. As duration of use increases there is reduction in menstrual flow. Around 20% of women experience amenorrhea (absence of menstrual bleeding) in the first year.
- Other side effects noted occasionally with levonorgesterel IUD include lower abdominal pain, complexion changes, back pain, breast tenderness, headache, mood changes and nausea although these decline with time and present in less than 3% of patients. As with other progestin only methods benign follicular cysts are common occurring in 8-12% of users. Most cysts resolve spontaneously and do not require any medical treatment;
- Some women may experience hormonal side effects such as mood changes or breast tenderness;
- Occasionally they can be expelled;
- Women using IUDs are at an increased risk of developing pelvic inflammatory disease (PID) within the first three weeks following insertion (which may cause infertility);
- In a small number of cases an IUD may perforate the wall of the uterus. This is usually the result of improper insertion.
Risks associated with IUDs
Development of PID is very rare despite earlier beliefs that they occur commonly in women using IUDs. The risk of PID is highest within the first 3 weeks following insertion, while after that the risk is minimal.Women with cervical infections caused by chlamydia or gonorrhoea at the time of insertion have a 3-5% chance of developing an infection in the first 20 days.Screening for vaginal and cervical infections should be carried out prior to insertion to reduce risk of infection being passed to the uterus.
PID among IUD users is also strongly related to the insertion process. Provision of skillful technique in aseptic settings for IUD insertion is critical for the prevention of PID.Pelvic infection may cause damage to the fallopian tubes which can lead to infertility and can also cause chronic pelvic pain.
Symptoms of infection to watch out for include:
- Pain or tenderness in lower abdomen;
- Unusual bleeding from vagina;
- Fever or chills;
- Discharge from vagina;
- Pain during intercourse;
- Burning sensation when passing urine.
Less than 1 out of 100 women who have been using an IUD for one year will fall pregnant.If you become pregnant see your doctor immediately to have the IUD removed. If the device is left in there is a high risk of miscarriage later in the pregnancy.
Perforation and Expulsion
In a small no of cases, about 1/1000 the IUD may be pushed through the wall of the uterus and require removal by operation.Perforation of uterus occurs most commonly if an IUD is inserted in the first 6 months after giving birth and can be increased as a result of provider inexperience.
Expulsion rates are between 2-3% for the copper IUD and 3-4% for the LNG intrauterine system. Expulsions usually occur in the first 3 months after insertion and are more likely to occur when IUDs are inserted in women who have not had a term pregnancy.
Women should check strings for changes in length and feel for the presence of the IUD stem. Around 4 weeks post-insertion a follow up visit to your doctor should be made. In women with the LNG-IUD resumption of normal periods may indicate that the IUD has been expelled.
Miscarriage and premature birth can occur in the rare occurrence that a woman becomes pregnant whilst an IUD is in place.
|For more information on different types of contraception, female anatomy and related health issues, see Contraception.|
- Family Planning W.A Sexual Health Services. Intra-uterine devices. URL: http://www.fpwa.org.au/healthinformation/informationsheets/iud/ (Accessed 12 July 2008)
- d’Arcangues C. Worldwide use of intrauterine devices for contraception. Contraception 2007; 75 : S2–S7.
- WHO. Progress newsletter No. 60 .The intrauterine device (IUD)-worth singing about http://www.who.int/reproductive-health/hrp/progress/60/news60.html
- Morgan KW. The Intrauterine Device: Rethinking Old Paradigms. Journal of Midwifery & Women’s Health 2006 51; 6: 465-472.
- Farmer L and S Everett. Non-hormonal contraception. Obstetrics Gynecology and Reproductive Medicine 2007 18(2): 32-38.
- Bilian X. Intrauterine devices. Best Practice & Research Clinical Obstetrics and Gynecology 2002; 16(2): 155-168.
- World Health Organisation, John Hopkins School of Public Health and US Agency for International Development. 2007. Family planning: a global handbook for providers. Chapter 9: Copper bearing intrauterine device Available from: http://www.infoforhealth.org/globalhandbook/handbook.pdf
- Family Planning NSW. May 2003. A new kind of intrauterine device. http://www.fpahealth.org.au/news/20030501_mirena.html
- Mazza D. Take a fresh look at IUDs: things have changed. Australian Family Physician 2002; 31(10): 903-907.
- Thonneau PF and TE Almont. Contraceptive efficacy of intrauterine devices. American Journal of Obstetrics & Gynecology 2008; 248-252