There are two ways to calculate the pregnancy cycle after transfer, which are according to the fertilization date and the fresh embryo transfer date. 1. Calculation according to the fertilization date: the calculation method starts from the patient’s fertilization date and subtracts the previous 14 days to get the date of the last menstrual period, and the number of days to conception is calculated according to the first day of the last menstrual period. 2. Calculation according to the day of fresh embryo transfer: the calculation method is generally based on the number of days of fresh embryo transfer, if the patient transfers three days of fresh embryo, the last menstrual period under normal circumstances minus 17 days. If the patient is using five days of fresh embryos, the sixth day blastocysts, the last menstrual period normally minus 19 days can be obtained. Both of these calculations are effective in confirming when the pregnancy cycle has begun, allowing for a more accurate projection of the due date.