Mannuelle ring that is levonorgestrel intrauterine slow-release system, contraindications are mainly in the following areas: 1. Suffering from abnormal vaginal bleeding, can not rule out that there is cervical cancer and endometrial cancer in women, reproductive tract tumor disease can not be placed levonorgestrel intrauterine extended-release system, in the former must be cervical cancer screening, scraping, clear diagnosis. 2. Suffering from uterine adenomyosis larger fibroids, resulting in the whole uterus is relatively large, the depth of the uterine cavity is more than 10 centimeters or the uterine cavity is particularly wide, deformation of the situation can not be placed levonorgestrel intrauterine slow-release system, easy to fall off or downward shift, can not play a contraceptive effect. 3. When the patient is allergic to the birth control ring, levonorgestrel intrauterine slow-release system cannot be placed. 4. If there is persistent bleeding and back pain after the implantation of the IUD, the IUD must be removed when symptomatic treatment is ineffective. In general, it is recommended to have regular check-ups after placing the levonorgestrel intrauterine system. For those who need to install this IUD, consult a specialist at the hospital.