The "modern" IUD has been around since the early 1960s when the first plastic devices became available for the sterile insertion of a plastic or combination plastic and metal device into the uterus. These IUDs were in widespread use for about 15 years.
All of that changed with the 1970 introduction of the Dalkon Shield—an IUD introduced with the purpose of lowering the spontaneous expulsion rate associated with some of the earlier models. In 1973 the first reports began appearing associating the Dalkon Shield with an increased rate of pelvic infection. Despite the fact that the IUD was removed from the market in 1975 many that had already been placed were not removed until years late.
Many lawsuits followed and A.H. Robbins, the company that marketed the Dalkon Shield, was bankrupted. The unfortunately effect of all the publicity, however, was that a very good method of contraception was blamed for many problems—many of them undeserved.
How do IUDs work?
How IUDs function is not perfectly understood. The majority of researchers however believe that IUDs work by inhibiting sperm transport rather than acting to prevent a fertilized egg from implanting in the uterine cavity. The best available scientific information dispels the myth that the IUD is an abortifacient.
Are all IUDs the same?
There are two choices available today.
The first, the Mirena IUD (Berlex Pharmaceuticals, Inc), is a plastic device embedded with the hormone, levonorgestrel. This particular IUD is designed to last 5 years (although it contains 7 years of hormone) but can be easily removed any time prior to that should a woman wish to conceive. The advantage of the Mirena IUD is that after 2 or 3 cycles women experience lighter and lighter periods—many women stop having periods altogether. The Mirena IUD is ideal for a woman who would like a spontaneous and safe method of contraception that is also seeking relief from otherwise heavy or painful menses and who wishes to avoid the inconvenience of a daily pill, a weekly patch or a monthly ring. Importantly, the Mirena contains no estrogen whatsoever! What little progesterone is in the IUD (about 20 micrograms per day) is largely confined to the uterus and causes only minimal levels of the progestin, levonorgestrel, in the blood stream.
The second IUD available today--ParaGard (Duramed Pharmaceuticals, Inc)—which is a device made of plastic and copper. This is a non-hormone containing IUD that can be left in place for 10 years.
Both IUDs are highly effective though the ParaGard does tend to cause an increase in menstrual blood flow.
Are there women who should not use the IUD?
There are very few women who cannot use the IUD. However, since the IUD can aggravate or incite pelvic inflammatory disease it should be avoided in women who have had a history of chronic pelvic inflammatory disease or a recent history of multiple sexual partners. A history of bacterial vaginosis is not a contraindication to its placement. There are very few absolute contraindications to the use of an IUD.