Birth Control Intrauterine Devices (IUDs)

An intrauterine device (IUD) is a small T-shaped plastic device that is placed in the uterus to prevent pregnancy. A plastic string is attached to the end to ensure correct placement and for removal. IUDs are an easily reversible form of birth control, and they can be easily removed. However, an IUD should only be removed by a medical professional.  

Currently in the United States, 2 types of IUDs are available: copper and hormonal. Approximately 2% of women who use birth control in the United States currently use IUDs. The most recently introduced hormonal IUD is the levonorgestrel intrauterine system (LNG IUS or Mirena). Worldwide, IUDs are the most inexpensive long-term birth control method available.

Hormonal and copper IUDs work in different ways. With a copper IUD, a small amount of copper is released into the uterus. This type of IUD does not affect ovulation or the menstrual cycle. Copper IUDs prevent sperm from being able to go into the egg by immobilizing the sperm on the way to the fallopian tubes. If an egg does become fertilized, implantation on the wall of the uterus is prevented because copper changes the lining of the uterus.

With hormonal IUDs, a small amount of progestin or a similar hormone is released into the uterus. These hormones thicken cervical mucus and make it difficult for sperm to enter the cervix. Hormonal IUDs also slow down the growth of the uterine lining, making it inhabitable for fertilized eggs.

Before an IUD is placed, a physical examination is important to make sure that the reproductive organs are normal and that no infections are present. The clinician will ask about medical and lifestyle history. Being open and honest is important when answering these questions. IUDs are not appropriate for every woman.

Before the IUD is placed, a woman should discuss any questions she has with her clinician. The clinician will also provide a consent form with detailed information about the IUD. The woman should make sure to read this form carefully and understand it before signing.

An IUD can be placed during an office visit and remains in place until a medical professional removes it. It can be inserted at any phase of the menstrual cycle, but the best time is right after the menstrual period because this is when the cervix is softest and when women are least likely to be pregnant. Women may be instructed to take an over-the-counter pain reliever an hour before insertion to prevent cramps. Women may also be given an antibiotic to prevent possible infection associated with insertion; however, some studies disagree about the benefit of antibiotics.

To place the IUD, a speculum is used to hold the vagina open. An instrument is used to steady the cervix and uterus, and a tube is used to place the IUD. The arms of the T shape bend back in the tube and then open once the IUD is in the uterus. Once the IUD is in place, the instruments are withdrawn. The string hangs about an inch out of the cervix but does not hang out of the vagina.

Cramps may be uncomfortable during insertion, and some women feel dizzy. Breathing deeply and trying to relax should prevent these problems. Women may want to have someone with them to drive them home after IUD insertion.

Once the IUD is placed, women can return to normal activities such as sex, exercise, and swimming as soon as they are comfortable. Strenuous physical activity does not affect the position of the IUD. Women can also use tampons as soon as they wish after an IUD is placed.

Women should never try to remove an IUD themselves. Serious damage can result. A clinician can usually remove an IUD very simply by carefully 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. If the IUD is being replaced, a new one can usually be inserted immediately.

Rarely, the cervix may need to be dilated and a grasping instrument is used to free the IUD. If this occurs, a local anesthetic is used.

Very rarely, surgery may be necessary. Women may require hospitalization if an incision is required to remove an IUD.

Women who are interested in using IUDs for birth control should contact their private doctor, health maintenance organization (HMO), or local Planned Parenthood health center. Not all clinicians insert IUDs, so ask in advance. Planned Parenthood states that the cost of the examination, insertion, and follow-up visit is $250-450. At some clinics, price may be based on income. Medicaid covers these services.

For one-time insertion of a copper IUD that lasts 10 years, the cost is approximately $400. This breaks down to cost less per year than most other forms of reversible birth control.

The copper IUD is the most commonly used type of IUD. It can be left in the body for up to 10 years. It can be removed at any time if a woman wishes to become pregnant or if she does not want to use it anymore.

The arms of this IUD contain some copper, which is slowly released into the uterus. The copper prevents sperm from making their way through the uterus into the tubes and prevents fertilization. If fertilization does occur, the copper prevents the fertilized egg from implanting on the wall of the uterus.

Hormonal IUDs that contain progesterone must be replaced every 5 years. They can be removed at any time if a woman decides she wishes to become pregnant or if she does not want to use it anymore. Hormones are in the arms of the IUD and are released slowly into the uterus.

The Mirena levonorgestrel-releasing intrauterine system (IUS) contains the hormone levonorgestrel (LNg), which is similar to progesterone. The LNg IUS causes cervical mucus to thicken to prevent sperm from entering the cervix and reaching the egg. Only about 1 in 1,000 women who use the LNg IUS experience accidental pregnancy in the first year. The LNg IUS reduces the risk of tubal pregnancies and pelvic inflammatory disease. It also dramatically decreases menstrual blood loss. It is approved to protect women from pregnancy for up to 5 years when used in the United States and 7 years in Europe and Asia.

How effective

The IUD is one of the most effective kinds of birth control available. According to the American College of Obstetricians and Gynecologists, only about 8 of 1,000 women who use the copper IUD become pregnant in the first year of use. According to Planned Parenthood, fewer than 3 women out of 100 who use the progestin IUD become pregnant during the first year of use. The success rate for women using the LNg IUD system is even greater. About 1 in 1,000 women who use the LNg IUD become pregnant in the first year of use. With continued use, even fewer pregnancies occur. A woman can increase her protection by checking the IUD string regularly and talking with her doctor immediately if she notices a problem.   

Advantages

• According to Planned Parenthood, more than 95% of women who use IUDs are happy with them.
  
  
• A woman using an IUD is always protected from pregnancy with nothing to remember. She does not need to remember to take a pill every day, for instance.
  
  
• IUDs start working right away and can be removed at any time.
  
  
• IUDs are relatively inexpensive.
  
  
• The risk of side effects is low.
  
  
• IUDs can be inserted 6 weeks after the delivery of a baby or after an abortion.
  
  
• Women who use a copper IUD after childbirth can breastfeed safely.
  
  
• An IUD is not felt by a woman or her partner during sex.
  
  
• Women who cannot use birth control pills because of cigarette smoking or conditions like hypertension may be able to use an IUD.
  
  
• Some women experience less menstrual blood loss and pain with hormonal IUDs.

Disadvantages  

A doctor must insert and remove an IUD. Serious complications from IUD use are rare.

IUDs come out during the first year of use in about 5% of women who use them. This is most likely to happen during the menstrual period and in women who have previously given birth. Women using IUDs should check their pads or tampons daily while menstruating and feel regularly to make sure the string is in place. If an IUD is expelled unnoticed, a woman may easily become pregnant. If pregnancy occurs while an IUD is still in place, the risk of miscarriage is 50% greater. This risk is decreased by 25% if the IUD is taken out as soon as possible. If the IUD is not removed, a risk of serious infection to the woman exists. Ectopic pregnancies in IUD users are half as likely as they are in women using no birth control. Ectopic pregnancies are more likely in women who use Progestasert than copper IUDs; however, the overall risk remains less than for women who do not use birth control. Of those using Progestasert who become pregnant, about half of the pregnancies are ectopic. However, to reiterate, the risk of ectopic pregnancy is much less than it is in women who do not use any contraception. Women using IUDs who suspect they may be pregnant should contact their clinicians immediately.

An IUD may puncture the wall of the uterus when it is inserted. This occurs in 1-3 of 1,000 insertions. Cramping and backache may occur in the first few hours after an IUD is placed. Bleeding may occur for a couple of weeks after an IUD is placed. Some women have increased menstrual pain and heavy periods while using the copper IUD, but these symptoms are decreased in those using the hormonal IUD. Pelvic inflammatory disease is also possible with IUD use, especially if a woman is not in a monogamous relationship and has an increased risk of  transmission of a sexually transmitted disease (STD).

IUDs do not protect against STDs. STDs can be worse in women who have IUDs, and the chance of getting an STD may be higher in women who use IUDs during the first 4 months after they are placed. IUDs are best for women in relationships in which both partners are monogamous.

Women who should not use an IUD

• Women who are pregnant or who have abnormal bleeding or cancer of the cervix or cancer of the uterus should not use IUDs.
  
  
• Women who have had pelvic inflammatory disease, gonorrhea, or chlamydia within the past 12 months should also not use an IUD. Women with other current reproductive organ infections should not use an IUD until their infection is resolved and their doctor says that an IUD can be used safely.
  
  
• Women with increased susceptibility to infections, such as those with leukemia, AIDS, and those who use intravenous (IV) drugs should not use IUDs.
  
  
• If a woman has abnormalities of the cervix, uterus, or ovaries that would make insertion dangerous, an IUD is not appropriate.
  
  
• Women who are allergic to copper, are having heat treatments, or who have Wilson disease (a rare disease in which copper accumulates in body tissues) should not use the copper IUD.
  
  
• For women who have heart disease, an artificial heart valve, or a ventricular septal defect that has not been repaired, a doctor will carefully evaluate whether an IUD is appropriate because of the possibility of infection.
  
  
• According to Planned Parenthood, because untreated infections associated with IUDs may cause infertility or difficulty becoming pregnant, IUDs are generally not recommended for women who have not yet had any children who may want them, women who want more children, and women who have had difficulty conceiving. However, in their discussion of IUDs, the Reproductive Health Technologies Project disagrees with this claim because IUDs are easily reversible.

At least monthly, women should check to be sure that they feel the string coming out of the cervix to make sure the IUD remains properly in place. To check for the string, sit or squat and with clean hands, insert the index or middle finger into the vagina until the vagina is felt. Do not pull the string. This may cause it to come out of place. If a woman does not feel the string, if the string feels too short or long, or if she feels the IUD itself, she should call the doctor.

Women who miss their periods or who notice unusual vaginal fluid or odor should call the doctor. Women who have severe abdominal pain or cramps, pain or bleeding with sex, unexplained fever and chills, or unexplained bleeding after the adjustment phase should call their clinician immediately. 

Women using IUDs should have a checkup following the first menstrual period after an IUD is placed and should have regular examinations every year.

Any woman using an IUD who suspects they she is pregnant should contact her clinician immediately.

|Web Links|

U.S. Food and Drug Administration, Protecting Against Unintended Pregnancy: A Guide to Contraceptive Choices

U.S. Food and Drug Administration, Birth Control Guide

American College of Obstetricians and Gynecologists, The Intrauterine Device

Planned Parenthood, Birth Control, Understanding IUDs

Emory Department of Gynecology & Obstetrics, Copper T IUD

Emory Department of Gynecology & Obstetrics, LNg IUD

Emory Department of Gynecology & Obstetrics, Progestasert IUD

Reproductive Health Technologies Project, Intrauterine Devices

Media file 1: Intrauterine device (IUD).

Media type:  Illustration

IUD, LNg IUD, Progestasert IUD, progesterone IUD, levonorgestrel IUD, copper IUD, copper T IUD, Copper T 380 A, birth control, contraceptive, prophylactic, pregnancy prevention, intrauterine device, birth control intrauterine devices, IUS, intrauterine system

Author: Omnia M Samra, MD, Clinical Instructor, Department of Obstetrics and Gynecology, Medical College of Pennsylvania/Hahnemann University.

Editors: Bryan D Cowan, MD, Director, Division of Reproductive Endocrinology, Professor, Department of Obstetrics and Gynecology, University of Mississippi College of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, ; Lee P Shulman, MD, Professor of Obstetrics and Gynecology, Head, Section of Reproductive Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.