Description
An IUD is a T-shaped plastic device about 3.5 cm long that is placed into the uterine cavity to prevent pregnancy. Small amounts of copper or a hormone are released into the uterus, blocking sperm from entering the Fallopian tubes and thus preventing fertilization. If fertilization were to occur, the IUD would prevent the fertilized egg from successfully implanting in the lining of the uterus. IUDs begin working immediately upon insertion and stop affecting fertility immediately upon removal.

How It Works
The FDA has approved two kinds of IUDs: the Copper T (Paragard ® ) IUD, which contains copper and can be used for up to 12 years; and the Progestin (Progestasert ® or Mirena ® ) IUD, which uses the hormone progesterone, the same as the hormone produced by a woman's ovaries during each monthly cycle. The progesterone causes the cervical mucus to become thicker so sperm cannot reach the egg. It also changes the lining of the uterus so implantation of a fertilized egg cannot occur. Progestasert ® can be used for up to one year. Mirena ® can be used for up to five years. The IUD can also be used as an effective method of emergency contraception (EC). While hormonal EC taken orally can be used for 72 hours after intercourse, an IUD can be inserted up to five days after unprotected intercourse for emergency pregnancy prevention.

Should You Use It?
You might want to use an IUD if you have had at least one baby (pregnancy stretches the uterus and reduces the chance that your body will expel the device), you are in a mutually monogamous relationship or are otherwise not at risk of contracting sexually transmitted infections (STIs), you have no history of pelvic inflammatory disease (PID), or you cannot use hormonal contraceptives. You should not use an IUD if you have an STI; IUD use increases the possibility that an STI (such as gonorrhea or chlamydia) will lead to PID, which can cause infertility, increased risk of ectopic pregnancy, and even death, if it goes untreated. You also shouldn't use an IUD if you might be pregnant or if you have certain cervical and uterine abnormalities as defined by your doctor.

Effectiveness
The most effective reversible method of contraception currently available, IUDs are 99% effective at preventing accidental pregnancy.

STI Protection
The IUD does not prevent the transmission of sexually transmitted infections, including HIV.

Advantages

• The most effective reversible method of birth control currently available in the United States.
• Copper T IUDs are effective for at least 12 years, Mirena ® for five years and Progestasert ® for one.
• An extremely safe, effective and failsafe method of contraception.
• IUDs are in place until removed by the health care provider. Many women report that they are more spontaneous about having sex, because the risk of pregnancy is so low.
• The ability to get pregnant returns immediately after removal of an IUD.
• Prevents ectopic pregnancies, life-threatening pregnancies that occur in the Fallopian tubes.
• Cost-effective over time.
• Can be used by women who cannot use estrogen-containing birth control pills.
• May be used by breastfeeding women.
• May be inserted immediately following the delivery of a baby or immediately after an abortion.

Disadvantages

• Some women may experience cramping, pain or spotting after insertion.
• Some women may experience longer menstrual periods or stronger cramps.
• Rarely, IUD use may cause pelvic infection or perforation of the uterus.
• Provides no protection against STIs.
• The initial cost of insertion is high.
• Must be inserted by a doctor, nurse practitioner, nurse midwife or physician's assistant.
• Your partner may feel the strings during intercourse.

Where to Buy It
You can get an IUD from your doctor, nurse practitioner, nurse midwife, Planned Parenthood or the health department. Not all clinicians insert IUDs, so check in advance. To avoid inserting an IUD into a woman who might be pregnant, most clinics insert IUDs when a woman has her period or within seven days after her last period began. If the risk of pregnancy can be excluded, it may be possible to insert an IUD at other times.

Follow Up
One of the biggest advantages to the IUD is that there isn't much follow-up after the insertion. All you have to do is check the strings once a month to ensure the device is still in place. However, one of the potential side effects of the Copper T IUD is a longer menstrual period and more intense cramps so you may want to visit your doctor for additional medications to regulate your period.

Contraception Overview