A study that included 12,000 women from around the world has found that using an intrauterine device (IUD) is linked to a reduced risk of cervical cancer. The study was not able to show that the use of IUDs actually caused the reduction, but the association was strong. Women who used IUDs had a one third less (about 33%) cervical cancer than women who didn't.
Why the link?? While not known, one good explanation is that the presence of an IUD causes changes in the immune system that help these women to fight off infection with the virus that causes almost all cervical cancer - the human papillomavirus (HPV). This will have to be tested.
Importantly, the authors of the study state that women should not take these results to mean that they should rely on IUDS as protection against infection with HPV. IUDs are one of the most effective methods of birth control, and this may turn out to be an added consideration when choosing a birth control method.