The last menstrual period is on March 25, and the due date is January 2 of the following year for regular menstruation. Usually, the due date is calculated from the first day of the last menstrual period, and the total length of pregnancy is 280 days. However, due to the variability of each woman’s menstrual cycle, the theoretical estimated due date may deviate slightly from the actual due date. According to the last menstrual period, the theoretical due date is calculated by subtracting three or adding nine to the month and adding seven to the date. Due to the many factors affecting pregnancy, it is recommended to go to the hospital and have a professional doctor check and determine the due date by combining the physical examination and imaging tests. Due to the many factors affecting pregnancy and the complexity of the situation, you should go to the local hospital to complete the relevant examinations and comply with the guidance of professional doctors.