This is the first in a three-part series of articles on intrauterine devices (IUDs). Here we look at the abysmal history of the IUD in America and explore the reasons for its lack of acceptance.

Today's intrauterine devices (IUDs) are the most effective, economical, and popular means of reversible contraception available. Worldwide, more than 100 million women rely on an IUD for contraception. In Europe, where standards of medical care most closely parallel our own, 25% to 30% of women who use a reversible method of contraception use an IUD. Why then, in the medically sophisticated and technologically savvy United States, is the IUD among the least popular, least trusted methods of birth control?

Blame it on the Dalkon Shield

The 1970s were the heyday of IUD popularity in this country. However, during that decade, a poorly designed and inadequately researched device--the Dalkon Shield--shattered the confidence of American women and their doctors in IUDs. Says Paul Feldblum, PhD, a senior epidemiologist at Family Health International: "At the time of the Dalkon Shield tragedy, the prevalence of IUD use in the United States was about 10%. It is now under 1%."

What was the problem with the Dalkon Shield? Most IUDs have one or two monofilament tail-strings attached to their base. When the device is in place, the tail-strings hang down from the opening of the cervix. They allow the user to manually confirm that the IUD is still in place, and they facilitate removal. Basically, removal involves pulling the IUD out by its tail-string, although this should only be done by a trained healthcare professional, never by the user herself.

The Dalkon Shield was oddly shaped and more difficult to remove than conventional T-shaped IUDs. Its design incorporated a mutifilament tail-string with greater tensile strength, so it wouldn't break on removal. Unfortunately, this multifilament tail-string proved to be a virtual on-ramp for bacteria to move from the vagina to the upper genital tract. And shortly after the Dalkon Shield's introduction in 1971, reports began to surface of septic abortions and upper genital infections. Some women died from these infections; many others were left sterile or with debilitating pelvic pain. As a consequence, in 1974, the Dalkon Shield was removed from the U.S. market. The ensuing legal action brought against the manufacturer (A.H. Robbins) led the firm to declare bankruptcy in 1985. By 1986, all but one manufacturer of IUDs had pulled out of the U.S. market over fear of litigation.

Mysteries, myths, and misconceptions

Today's IUDs are nothing like the Dalkon Shield--in design or practical use. Nonetheless, many U.S. women, and their physicians, remain generally distrustful of all IUDs. Besides being unfairly tarred with the Dalkon brush, another probable reason for this lack of acceptance is confusion over how IUDs work. Actually, it's easier to say how they don't work. IUDs are not barrier contraceptives like the diaphragm or cervical cap; they don't block the movement of sperm cells upward into the uterus. Nor, contrary to popular mythology, are IUDs abortifacients--they do not induce abortion of an implanted fertilized egg.

There are two types of IUD: one is copper-covered and releases copper ions into the uterus; the other is hormone-based and releases small amounts of progestin into the uterus. The copper-based system is thought to block fertilization by reducing sperm cells' ability to swim and reach an egg; exactly how is not known. The probable mechanisms of action for progestin-releasing IUDs include thickening of cervical mucous and changes in the uterine lining, which hinder the upward movement of sperm cells to the fallopian tubes, as well as disruption of ovulation and direct interference with fertilization. But again, the precise mechanisms of action are not known.

The odds of a 'comeback'

Three IUDs are on the market in the U.S. today--the most recent (Dec. 2000) being the 5-year progestin-releasing Mirena from Berlex Laboratories. A 1-year progestin-releasing device (Progestasert/ALZA Corporation) and a 10-year copper-releasing device (Paragard/Ortho-McNeil) are also available.

The range of available IUDs in this country has never been better. So, any chance of an IUD renaissance? FHI's Feldblum comments that "their high effectiveness, long duration of use, and favorable safety and cost profiles render modern IUDs better for many women than competing methods," such as hormonal implants or sterilization. "As more service providers and potential users learn of the many benefits," says Feldblum, "and as newer evidence counters the inaccurate beliefs and fears that plague the IUD, the general perception of the method can only improve. There's no place to go but up!"

--SexHealth.com