Pregnancy is usually regular menstrual cycle, according to the last menstrual period to project the number of days of pregnancy, and then according to the number of days of pregnancy to project on the number of months and weeks, seven days for a week, four weeks for a month, usually irregular menstrual cycle, you can go to the hospital through the ultrasound after the estimation. Women usually have a regular menstrual cycle, counting from the first day of the last menstrual period to the present date for the number of days of pregnancy, and then push up the number of days of pregnancy, seven days for a week, four weeks for a month, you can know specifically when you are pregnant. Women who have irregular menstrual cycles and don’t remember when their last menstrual period came, are advised to go to the hospital for an ultrasound, which is generally used to estimate the age of the fetus based on the buds and the length of the head and buttocks in the early stages of pregnancy, and to understand how many months and weeks the pregnancy lasts. If you are pregnant and do not know how long you are pregnant, you can go to the hospital and ask a medical professional to calculate your pregnancy.