When is the longest duration of chorionic villus injection for fertility preservation, generally based on the symptoms, if the symptoms are mild and significantly reduced, you can stop the injection immediately, if the symptoms are severe can continue for about 12 weeks, the specific need to comply with the doctor’s advice. Chorionic injection is generally used in the early stages of pregnancy when the development of the embryo is unstable, the body’s hormone levels are abnormal, abdominal pain or vaginal bleeding symptoms of preeclampsia. If the symptoms are mild, and the symptoms are relieved after the injection, then the medicine can be stopped, but if the symptoms persist without significant improvement, it is generally recommended that the injection should not be used after 12 weeks of pregnancy. Because after 12 weeks, as the embryo develops and matures, the placenta will gradually grow and can provide hormones for the development of the embryo, so there is no need to take chorionic villus injection to protect the fetus. After the injection, you need to observe the changes in your body at any time. If there is no effect for a long time, you should consult the doctor immediately to see if the medication needs to be adjusted under the doctor’s examination and guidance.