Types of IUDs
There are many brands of IUDs. While only one brand (Paragard T 380A) is available in the United States, more variety is seen in other countries. For example, seven brands (Flexi-T 300, GyneFix, Multi-Safe 375, Multi-Load Cu 375, Neo-Safe T380, Nova T 380, T-Safe 380A) are available in Great Britain. There is also a hormonal device that is placed in the uterus, the Mirena IUS.
Most types of IUDs have a plastic T-shaped frame that is wrapped with copper or has copper bands. Some IUDs, such as the Nova T 380, also contain a small amount of silver. The GyneFix does not have a T-shape, but rather is a loop that holds several copper tubes.
Effectiveness and mechanism of contraception
The effectiveness of an IUD ranges from 98% to over 99% depending on the brand.
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.
IUDs can not protect from STDs, and if an infection is caught while using an IUD it may be more likely to spread to the uterus.
Contraindications
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IUDs are not recommended for women with sexually transmitted diseases (STDs) or pelvic inflammatory disease (PID). Presence of an IUD increases the risk of an STD progressing to PID, and increases the risk of a PID causing infertility.
While nulliparous women are somewhat more likely to have side effects, this is not a contraindication for IUD use. The GyneFix is more recommended for nulliparous women, as it appears to be better tolerated in that population. |
Side effects and complications
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IUDs may make menstrual periods heavier and/or more painful, especially for the first few months after they are inserted. Because it is smaller, the GyneFix is less likely to affect periods than T-shaped devices.
Insertion of the IUD may introduce bacteria into the uterus. A course of antibiotics is frequently prescribed for use immediately after IUD insertion.
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While rare, complications include expulsion and uterine performation.
The risk of ectopic pregnancy to a woman using an IUD is lower than the risk of ectopic pregnancy to a woman using no form of birth control. However, of pregnancies that do occur during IUD use, a higher than expected percentage is ectopic.
