If you usually have regular menstruation and your last menstrual period was on April 12, your due date will be around January 19 next year. The algorithm for the due date is the month of the last menstrual period plus nine or minus three, and the date plus seven. It is worth noting that the date of the last menstrual period is the date of the Gregorian calendar. If you only remember the date of the last menstrual period in the lunar calendar, you need to convert it to the Gregorian calendar date to calculate the expected date of labor. The date of the last menstrual period is the first day of menstruation, not the last. The due date is not the actual date of delivery and may vary by one to two weeks. During pregnancy, it is important to take plenty of foods high in protein, vitamins and folic acid, and to have regular labor checkups.