The month of pregnancy cycle can be calculated by the last menstrual period and ultrasound. 1. Last menstruation: The pregnancy cycle of a pregnant woman can be counted from the first day of the last menstrual bleeding, every 7 days is a week, every 4 weeks is a month, and the normal pregnancy cycle totals 10 months, that is, 40 weeks, 280 days. If a pregnant woman delivers within 38 to 42 weeks, she is considered full-term. This method of calculation is more common and convenient, and is suitable for women who have regular menstruation. 2. Calculation through ultrasound: You can have an ultrasound examination in early pregnancy. The doctor will project the pregnancy period through the size of the gestational sac, the embryonic tissue, and measure the head and hip length of the fetus. You can consult your doctor after the examination and the doctor will explain in detail. During pregnancy, you should follow the doctor’s instructions to take obstetric checkups on time. If you have any questions, it is recommended to consult a professional doctor for guidance.