When you are pregnant, the week of pregnancy is calculated as four weeks to a month. That is, four weeks of pregnancy is one month of pregnancy, eight weeks of pregnancy is two months of pregnancy, and so on. For pregnant women with regular menstruation, pregnancy is usually calculated based on the last menstruation, from the first day of the last menstruation, until the present time, you can calculate the number of days of pregnancy. Seven days is a pregnancy week, four weeks is a month, so as to calculate the pregnancy week and month. For pregnant women with irregular periods, ultrasound can be used to determine the week of pregnancy and then calculate the month of pregnancy. The entire course of pregnancy is about 40 weeks, or ten months. However, this is only an estimated time of the expected date of delivery. Some pregnant women may deliver in less than 40 weeks, while some may deliver in more than 40 weeks, which still depends on each pregnant woman’s situation. Pregnant women should take regular pregnancy checkups and seek medical attention if there are any abnormalities.