How does an IUD work?

[dead0man]

Potential girlfriend wears one and I was just wondering how one works. This can obviously have fairly important side effects to me. How safe are they against un-wanted pregnancies? Thanks in advance.
deadman

[flodnak]

A link with more than you ever wanted to know:
http://www.plannedparenthood.org/BIRTH-CONTROL/IUD.HTM

A summary: There are two types of IUDs, the “traditional” type which is just plastic and copper and a newer version that slowly releases a hormone. No one really knows how the traditional style works, but it appears to keep the sperm from getting to the egg somehow. The hormone type thickens the cervical mucus to act as a natural spermicide, and thins the uterine lining to prevent implantation if any sperm do make it through. Both are among the safest birth control methods on the market as far as preventing pregnancy goes. Obviously there’s no protection against swapping various interesting diseases.

[3waygeek]

I remember reading years ago that the idea for the IUD came from nomadic Arab tribesmen, who would put pebbles into the wombs of their female camels to keep them from getting pregnant during long journeys.

For some reason, copper seems to be used in a lot of IUDs (e.g. the infamous Copper 7); wouldn’t this be a bit risky, depending on the uterine pH? I know that the vagina is somewhat acidic, in order to stop any invading bacteria (and a significant percentage of sperm cells) – does anyone know if the uterine environment reacts with copper and what effects that could have?

[kanicbird]

after reading the link, i see a potential problem. the IUD has a monofiliment line attached to it and that line supposially extends into the vaginia. unless it actually extends out of it, what would prevent the partner from getting stuck w/ this line. could the line actually enter the male?

[Maxwell_Edison]

I was reading about this just last night. The theory in the book I read was that the copper causes a kind of mild inflamation in the uterus that prevents pregnancy from occuring. It went on to say that the amount of coppper released daily was only 1/30 of the amount an adult needs everyday.

[Myron_Van_Horowitzski]

While other methods mostly work by keeping the sperm and egg apart, IUDs work by preventing the implantation of a fertilized egg. This is why some pro-life people are against them.

While effective, they can be hazardous if the woman using them is prone to ectopic pregnancy. (This is when the fertilized egg implants itself in one of the Fallopian tubes - highly dangerous and frequently fatal).

[3waygeek]

While other methods mostly work by keeping the sperm and egg apart, IUDs work by preventing the implantation of a fertilized egg.

That’s what I’ve always heard. However, the Planned Parenthood site flodnak linked to says that IUDs prevent fertilization, not implantation. I suspect they probably know a bit more about this stuff than we do.

Of course, their definition of fertilization might include subsequent implantation; a useful obfuscation to keep the pro-lifers at bay (not that it’d do much good, since PP provides/refers other, less ambiguous services that pro-lifers strongly oppose).

[lolagranola]

I also always believed that the IUD prevents implantation, so I just did some quick research. According to Reproductive Health Development, it does several things.

Mechanisms of Action
Various hypotheses have been advanced over the years about the mechanisms of action of IUDs, including interference with sperm transport, ovum transport or development, fertilization, and implantation. Until about 1980, it was believed that the IUD worked mainly by causing an inflammatory response to a foreign body in the uterus, thereby interfering with implantation of a fertilized egg in the uterine wall. The informed consensus now has changed.

Studies support the conclusion that Copper IUDs prevent fertilization by reducing the number and viability of sperm reaching the egg, and by impeding the number and movement of eggs into the uterus. It is believed that the continuous release of copper from the coils and sleeves of the Copper T 380A into the uterine cavity enhances the contraceptive effect of the IUD.

Ideal Candidates for Copper T380A IUDs
The Copper T 380A IUD is recommended for women who:

have had at least one child;
are in mutually monogamous relationships;
have no history of pelvic inflammatory disease (PID);
choose not to use hormonal contraceptives.

Women Who Should Not Use Copper T380A IUDs
The Copper T 380A IUD should not be inserted in a woman who:

is pregnant or is suspected to be pregnant;
still retains a previously inserted IUD;
has a known or suspected malignancy of the genital tract, including undiagnosed vaginal bleeding and an unresolved abnormal Pap smear, or a severe uterine abnormality.
had postpartum endometritis or postabortion infection in the past three months;
has Wilson’s disease or a known allergy to copper;
has genital actinomycosis.

Many of the contraindications to IUD use have to do with infections. An IUD is not an appropriate method for a woman who:

has a sexually transmitted disease (STD) including a lower genital tract infection, such as gonorrhea or chlamydia;
is at a high risk for STDs because she or her partner has multiple sexual partners;
has acute pelvic inflammatory disease or a history of pelvic inflammatory disease;
has untreated acute cervicitis or vaginitis, including bacterial vaginosis, until infection is controlled;
has conditions associated with increased susceptibility to infections with microorganisms. Such conditions include, but are not limited to, leukemia, acquired immune deficiency syndrome (AIDS), and intravenous drug abuse.

If a woman cannot predict reliably whether she or her partner will be in a monogamous relationship, it would be prudent for her to adopt another contraceptive. A woman at risk for a sexually transmitted disease may also be at risk for transmission of the HIV virus; she should have her partner use a condom since an IUD does not protect against AIDS.

There are a few other considerations, all listed on the site. Hope it helps. I know I sure learned a lot.