If you are pregnant in June, your due date will be in March of the following year. The menstruation is regular and the first day of the last menstruation is remembered correctly. Generally the due date is calculated from the first day of the last menstruation, the month plus nine and the date plus seven. If the patient has irregular menstruation, it cannot be calculated exactly in this way. In general, it is important to compare the weeks of pregnancy indicated by the early ultrasound. If the number of weeks taken by early ultrasound does not agree with the menstrual projection, and the results differ by more than one week, the due date needs to be adjusted, and the patient can only continue to project her due date according to the number of weeks projected by ultrasound, so early ultrasound is especially important. If the last menstrual period is unclear and early ultrasound is not available, we should combine the time of positive urine HCG, the time of fetal movement and the week of gestation indicated by ultrasound in the middle of pregnancy to roughly estimate the expected delivery date.