The due date for an April pregnancy is December of the current year or January of the following year. The formula for calculating the expected date of delivery is as follows. The month is calculated by subtracting three or adding nine from the time of the last menstrual period, which needs to be checked together with the time of the last menstrual period and the result of the ultrasound examination. If the pregnancy is detected in April, the due date will be December of the current year if the last menstrual period is in March, or January of the following year if the last menstrual period is in April; the date is obtained by adding seven to the date of the last menstrual period. The date is obtained by adding 7 to the date of the last menstrual period. The last menstrual period is the first day of the last menstrual period before pregnancy. Because some women’s menstrual cycles are not very accurate, it is also necessary to verify the due date in conjunction with an ultrasound examination, which is usually taken between 11 and 13 weeks of gestation for verification and evaluation of the due date.