If the pregnancy is detected and then not detected again after the next day, there are several possibilities: First, the first detection error, if the patient does a urine test, due to the concentration of such hormone levels in the urine is relatively low, so there may be a false positive phenomenon, and the next day may not be detected again. Second, it may be a miscarriage. If the patient has been having vaginal bleeding after detecting the pregnancy, this situation should be considered as pre-eclampsia miscarriage. When the test is not detected again after a day, it is because the embryonic tissue has flowed out or it is a biochemical pregnancy, which causes the hormone level of physical strength to be relatively low, so it is not detected, in this case it is better to go to the hospital to do vaginal ultrasound to see the condition of the uterine cavity.