IUD
The IUD (intrauterine device) is a small device placed inside the uterus for birth control. It is thought to primarily prevent fertilization by creating an intense inflammatory reaction inside the uterus that is harmful for sperm, either destroying sperm or making it nearly impossible for sperm to reach the fallopian tubes. Secondarily, the IUD also makes the uterus unsuitable for implantation.
Although much more popular in the 1970's, the IUD has become a victim of bad press - due to infection problems with one particular IUD, the Dalkon Shield. Product liability has resulted in removal of many IUDs by the manufacturers, even though there is no intrinsic problem with these other IUDs.
There are now only 2 IUDs available for use in the United States: the more common copper T 380-A (Paragard) which is effective for 10 years, and a progestin-releasing Progesterone T (Progestasert) which is effective for 1 year. Both are safe, effective, and convenient to use.

Effectiveness
The failure rate of the Paragard IUD after one-year typical use is less than 1%; for the Progestasert IUD, it is less than 1%.

Insertion
A woman in a monogamous relationship who has already delivered a child is an excellent candidate for the IUD. Theoretically, women at risk for pelvic infections may be more predisposed to developing further infections with the IUD. This could ultimately lead to scarring of the tubes and sterility. The clinician will screen for appropriate candidates. Some anatomic pelvic abnormalities and certain medical conditions may make the IUD a less desirable birth control method. Insertion is usually done in the office with no need for any anesthesia. Removal of the IUD is relatively easy and needs to be done by a clinician.

Proper Use
Since the IUD can spontaneously be expelled or perforate (rarely) through the uterus, checking for the IUD string is advised before intercourse, especially the 1st month after insertion.

Advantages
The IUD is highly reliable and needs little attention once it is inserted. It is a method with high client satisfaction. The Paragard IUD, potentially good for 10 years, is the most economical method of birth control. Use of the Progestasert results in less pain and bleeding with menses.

Disadvantages
The Paragard IUD tends to cause somewhat heavier and more painful menstrual periods. If pregnancy does occur with an IUD in place, there is more danger of miscarriage and infection. Pelvic infections can lead to sterility because of subsequent tubal scarring. Although this is an extremely rare complication, women who haven't had children or who have recent pelvic infections may not be ideal candidates for an IUD. Progestasert users may have a higher incidence of ectopic pregnancy (pregnancy in the fallopian tube instead of the uterus).