The month of pregnancy can be calculated according to the time of menstruation or according to the result of the maternity test. 1. Calculated according to the time of menstruation: If a woman has a regular menstrual cycle, the pregnancy can usually be counted from the first day of the last menstrual period. Usually, 7 days of pregnancy is one week, and 4 weeks of pregnancy is one gestation month. 2. Calculated according to the results of the maternity test: If a woman’s menstrual cycle is irregular or she can’t remember the time of her last menstrual period, she can undergo an ultrasound examination, which is capable of determining the range of the fetus’s biparietal diameter, femur length, head circumference, and abdominal circumference, which can help estimate the duration of the pregnancy. It is recommended that pregnant women can go to the hospital for the examination and the doctor will estimate the month of pregnancy based on the results of the examination. In addition, women should avoid having sexual relations in the early or late stages of pregnancy. During pregnancy, it is necessary to go to the hospital regularly for maternity checkups, ensure enough rest, and eat a diet rich in protein and vitamins, such as eggs, milk, green vegetables, tomatoes, strawberries, dragon fruits and so on.