Jophiel wrote:
I never trusted IUDs. I've never seen anyone able to definitively say how they work, hence I view them about as favorably as I would voodoo or wearing a scary mask to frighten off the stork.
You know, modern IUDs really don't deserve the bad rep they've gotten. The early ones definitely had problems, but I had to do a report on them for my human sexuality class a couple years back, and it was interesting to note that, yes, while there is a small risk with IUDs, the chances of being rendered infertile or dead as a result of pregnancy and childbirth are much higher than the same chances as a result of an IUD mishap.
I think the squeamishness is due to the nature of IUDs. The idea of putting a foreign object not only in one's body but in one's UTERUS just scares people. Add onto that the fact that there is a minute risk of the thing working its way into or even completely through the myometrium and people just shudder and say "no thanks." Then, of course, there's the horror tales about the early ones in which no one ever seems to mention that modern IUDs are much safer.
As for how they work, here:
Wikipedia wrote:
The presence of a device in the uterus prompts the release of leukocytes and prostaglandins by the endometrium. These substances are hostile to both sperm and eggs; the presence of copper increases this spermicidal effect. Although the only experimentally demonstrated effect is spermicidal/ovicidal, it is possible the IUD may rarely prevent the development of embryos.
In other words, the prevent fertilization and as a last resort, they interfere with implantation.
Danger of expulsion is greater if you haven't been pregnant than if you have, so its better for women that have already had kids.