When choosing between the Kyleena, Mirena, and Jaydess intrauterine devices, it's important to consider factors such as effectiveness, size, and hormone content. Both the Kyleena and Mirena are highly effective for up to 5 years and have similar costs. They are both based on levonorgestrel, a type of progesterone hormone. In terms of weight gain, studies have not shown a significant difference between the two hormonal IUDs or the copper IUD. Ultimately, it's important to discuss your options with your doctor before making a decision on which contraceptive method to use.