If clinically the stomach pain occurs on the 45th day of pregnancy, the most common possibility is that it is caused by a pre-miscarriage. In addition, not only can there be stomach pain, but also a small amount of vaginal bleeding can occur in severe cases. It is recommended that an ultrasound be performed in a timely manner to see if the size of the gestational sac matches the number of days since menopause. If so, blood HCG and progesterone tests are recommended. Progesterone is often relatively low, it is recommended to take oral progesterone pills for treatment, mainly to inhibit the contraction of uterine smooth muscle, so that abdominal pain can be reduced to achieve the purpose of tranquilizing the fetus. In addition, if at 45 days after menopause, no ultrasound examination has been done in the past but suddenly appeared stomach pain, this situation must be ruled out the possibility of ectopic pregnancy. It is recommended to do ultrasound examination to find out whether there is a gestational sac outside the uterine cavity, once found in the case of extrauterine gestational sac, clinical timely conservative treatment or surgical treatment.