A cаse-cоntrоl study оf contrаceptive devices аnd infertility found prior use of intra-uterine devices (IUDs) in 89 of 283 infertile cases. In contrast, 640 of 3833 fertile control women had used IUDs. Calculate the odds ratio of having used IUDs between Infertile and fertile women. IUD Infertility Cases Fertile Cases Previous Use 89 640 No Previous Use 194 3193