Level 1: The role of the pregnancy periodic table. The pregnancy periodic table refers to the various stages that a woman goes through after conception, from conception to delivery. By understanding the pregnancy cycle chart, women can better understand their physical condition and fetal development. At the same time, for couples who want to get pregnant, they can also plan the time of conception according to the pregnancy cycle chart to improve the success rate of conception. Level 2: Contents of the pregnancy periodic table The pregnancy periodic table generally includes the following contents: menstrual period, ovulation period, fertilization period, implantation period, embryonic development period and pregnancy period, etc. Each stage has its specific physiological changes and symptoms