Placed in the uterus, IUDs act by inhibiting fertilization and provide contraception for several years. There are 2 types, copper devices and devices delivering a drug acting like a hormone (progesterone).

Their contraceptive efficacy is comparable to that of strictly adhered-to oral estrogen/progestogen contraceptives ("the pill"), and even better than oral contraception not strictly adhered to. The other advantages of the IUD are not having to worry daily about contraception, the lack of hormonal effects for copper devices, and a lower number of extra-uterine pregnancies than in the absence of contraception. IUDs are a first-line method of contraception for patients presenting certain pathologies, certain medical histories or taking certain treatments, as well as during breastfeeding and immediately after pregnancy. The IUD is also an effective alternative to emergency contraception. IUDs sometimes cause period pains, menstrual disorders (bleeding, deceptive lack of bleeding), and rarely infections shortly after fitting. In women who have never given birth, expulsion of the IUD is more common and fitting is frequently more painful, but that should not prevent their use.

©Prescrire July 2009

Source: "Dispositifs intra-utérins, alias stérilets" Rev Prescrire 2009; 29 (304): 113-119.
"Intrauterine devices" Prescrire International 2009; 18 (101): 125-130.

- More articles in Prescrire's "Spotlight"...