Onward!

Milk does a body good, however too many posts about heat pads, righteous pharmacists, and refusal-to-treat bills don't. So, enough backward steps for now; it's time to learn something new. And what can be newer than a birth control method that's been in use for thousands of years, namely the intrauterine device (IUD)?

The IUD is a small device that works inside the uterus. Worldwide, this is the most commonly used reversible method of birth control. IUDs were used thousands of years ago, and the "modern" devices (Ota ring) have been around since the early 1900s. There are many types of IUDs, but overall we can classify them based on content, and form. The older IUDs don't release any substances and are called nonmedicated (inert). IUDs that release either copper, silver, or hormones are medicated IUDs. Based on form, we have framed IUDs--the body of the device is a semi flexible plastic frame, and frameless--no frame. [For a more detailed classification, see this post.]

If there's a birth control method that can be seen as the "poster child" of how misinformation prevents women from taking advantage of something that has tremendous potential to benefit them, it's the IUD.

There are two major misperceptions about using an IUD: the risk of acquiring an infection, and the IUD's mechanism of action. Let's see if we can shed some light on these misperceptions.

Infection Risk

In 1970, the Dalkon Shield, a nonmedicated, framed IUD, was introduced in the United States. This IUD had a plastic frame and an attached tail made of several filaments braided together (multifilament). In 1974 a report was published that described 12 cases of septic, second-trimester abortions, five of which were fatal, in women using IUDs. The deaths were the result of infectious complications. Of the 12, a Dalkon Shield was used by 10, and a [WARNING, graphic picture] Lippes Loop by 2. The report raised suspicion that there might be something about the design of the Dalkon Shield that increased a woman's risk of widespread infection.

After the report, the manufacturer of the Dalkon Shield suspended sales, and the sales were never resumed. Despite the fact that in October 1974 the FDA concluded that the safety of the Dalkon Shield was not significantly different from that of other IUDs, the manufacturer was sued and forced into bankruptcy.

So, was the FDA wrong? No it wasn't. Unfortunately, it wasn't a match for sensationalistic media reports and [I shall refrain from characterizing them] lawyers.

During the lawsuits against the IUD manufacturer, a number of studies appeared that claimed a strong correlation between the use of a Dalkon Shield and an increased risk of pelvic inflammatory disease (PID). Those studies were later discredited and their conclusions were shown to have been flawed.

Briefly, the height of IUD use in the U.S. coincided with the sexual revolution. The main risk for acquiring PID, regardless of IUD use, is having sex with many partners, or with a partner who has multiple sexual contacts. Also, at the time the IUD deaths occurred, abortion was still illegal in the U.S.*

Regarding the actual facts about IUD use and the risk of PID:

--The risk of PID due to an IUD is very low.

The single most important risk factor for PID is having multiple sexual partners, or a partner who has multiple partners (because this increases your sexually transmitted infection [STI] exposure risk). If your risk of acquiring a STI is low, so is your risk of developing PID while using an IUD.

--Long-term use of copper- and hormone-releasing IUDs results in pelvic infection rates comparable to those seen in Pill users.

--PID risk is highest during the 20 day after IUD insertion.

The risk is highest during this time because that's when bacteria may be introduced into the uterus by the IUD insertion process. Briefly, the vagina is not sterile; it's normally full of bacteria (this is normal and, as long the bacteria stay in the vagina they're not harmful). In contrast, the uterus is sterile relative to the vagina. And so are the IUD and its insertion device. Of course, in order for the sterile IUD to get from its sterile package to the sterile uterus, it has to pass through the vagina. During this insertion process, some of the vaginal bacteria may be introduced into the uterus, causing a localized inflammatory reaction. This is a normal body response and it usually resolves naturally. However, if a vaginal (or pelvic) infection is already present, the IUD insertion may introduce harmful bacteria into the uterus (or may aggravate an already existing pelvic infection), causing or worsening PID.

Note: because of the increased risk with insertion, as a general rule, if you have an IUD inserted it's best if you leave the IUD in place up to its maximum lifespan (5, 10 years, or decades), rather than have it routinely taken out and reinserted earlier. (Obviously, if you decide you want to stop using the IUD, you can have it removed at any time.)

--PID that develops after the first month of IUD use (unrelated to the insertion process) is caused by an STI, not the IUD.

Mechanism of Action

The main mechanism by which the IUD offers pregnancy protection is by preventing the union of egg and sperm (fertilization). IUDs are spermicidal--they have a direct effect on sperm, killing them. The IUD also impedes the movement of eggs, and the hormone-releasing IUDs thicken the cervical mucus, making it more difficult for sperm to get into the uterus. One additional mechanism, for the hormone-releasing brands, is the inhibition of ovulation. The hormone (a progestin) prevents the ovary from releasing an egg. Also, the hormone has a direct effect on the lining of the uterus; it keeps the lining thin and inhospitable for implantation (the burrowing of the fertilized egg into the uterine lining).

Even after the Dalkon Shield was recalled and the incorrect studies were exposed, in the United States, lawyers triumphed over facts. IUD manufacturers ceased distribution of IUDs for quite some time and currently, American women only have access to two, older IUD types: the ParaGard (TCu-380A) and the hormone-releasing Mirena.

Less than 1% of American women use the IUD as a birth control method (female sterilization is the most popular method of birth control in the United States). This is in contrast to the rest of the world, including third world nations, where the IUD is the most popular method of reversible birth control. I mention this not because you should use the same birth control method used by women in other parts of the world. Rather, I'd like you to take a moment and ponder the reality that women in third world countries, and pretty much everywhere else in the world, have far more birth control options than you do!

Interestingly, in light of all the misinformation and negative publicity about IUDs, you'd think no one in America likes this birth control method. Not true. The IUD is a favorite method used by female Ob/Gyns for their own birth control needs. Also, the women who use the IUD love it--96% of U.S. women using an IUD view their method of birth control favorably. By comparison, 94% of Pill users rate their method favorably, as did 93% of users of sterilization, and 90% of condom users, while only 76% of diaphragm users and 74% of rhythm method users have favorable views of their methods.

Bottom line: The relationship between the IUD and PID is often misunderstood and misstated, and so is the IUD's mechanism of action. This deprives you of options and keeps you from making informed decisions about something that has the potential to benefit your lifestyle and your health.

In my next IUD-related post I'll go over the use of the hormone-releasing IUD for menstrual management.

*There's a very good review article, The Dalkon Shield Saga by Dr. Michael L Cox. Unfortunately, it's not available for free.