Frozen embryo transfer on the 12th day a little brown discharge, some are due to normal embryo implantation process of a small amount of bleeding or various reasons caused by the aura of miscarriage, but also some patients are due to ectopic pregnancy, a small number of patients are other gynecological problems appear. 1. Embryo implantation: due to the embryo implantation process may cause a small amount of endometrial capillary rupture, resulting in a small amount of bleeding, causing vaginal brown discharge, most of the bleeding is transient, most do not need special treatment; 2. Pre-eclampsia: there are also a small number of embryos that fail to survive the implantation, when there are various reasons for the embryo underdevelopment or cessation of embryonic development, the blood hormone level will also change, that is, with the use of birth control medication, there are women who will have relatively early bleeding symptoms. 3. Ectopic pregnancy: the embryo landing position is not good, resulting in abnormal bleeding will significantly increase the chances, such as: tubal pregnancy, uterine horn pregnancy and other ectopic pregnancy. 4. Other gynecological problems: there are cervical inflammation or cervical or vaginal tumors, and some vaginal bleeding will also occur. There may be other reasons for the brown discharge on the 12th day after frozen embryo transfer, and you need to actively do the examination and follow the doctor’s instructions.