You can find out if you are just pregnant, but you can’t undergo a black and white ultrasound examination because a black and white ultrasound examination can observe whether there is a pregnancy sac in the uterus or not. The duration of pregnancy is relatively short, and the formation of the gestational sac needs to be around 42 days, and the gestational sac has not yet formed in a new pregnancy, so it is not necessary to carry out a black-and-white ultrasound examination. You can take a blood test for progesterone, including blood HCG and urine HCG, and generally urine HCG is positive for pregnancy and negative for non-pregnancy. For example, the normal value of blood HCG is 0-5 IU/L. If it exceeds this range, it means that conception has occurred. If pregnant, progesterone may increase on top of the pregnancy. If abdominal pain or bleeding occurs during this period, you need to go to the hospital at any time for observation and prophylactic birth control with medication.