If the morning urine test is positive but turns negative in the afternoon, clinically, the main reason is that the days of menopause are still relatively short, so the HCG level in the morning urine is relatively high, and the morning urine test will reveal a positive result. In the afternoon, the HCG level in the urine decreases, and when you drink a lot of water, it dilutes the urine and gives a negative result. There is no need to be nervous, it is recommended to test again the next day using the morning urine. If necessary, it is also recommended to go to the hospital for a blood test for HCG, and it is recommended to have another blood test every other day. If the result of the HCG test doubles the next day, it is very likely that the pregnancy is intrauterine. It is recommended that if there is no discomfort, you can go for an ultrasound examination around 45-50 days after menopause.