The purpose of creating a card after pregnancy is to facilitate the understanding of the pregnancy checkups, so that the information of prenatal checkups can be stored in a unified file for easy access, and the creation of a card during pregnancy is conducive to dynamic observation of the fetal growth and development and the health condition of the pregnant woman. For example, the fetal femur length, biparietal diameter, amniotic fluid volume and other indicators, for women suffering from hyperemesis and gestational diabetes can also dynamically observe the changes in blood pressure and blood sugar, providing a basis for the doctor’s clinical use of drugs. Some women have difficulty remembering their last menstrual period, so after the card is created, it can be clearly recorded in the pregnancy file, which is convenient for doctors to assess whether the fetus is developing according to the time of menopause and the indicators of clinical examination, and is also helpful for pregnant women to grasp the expected time of delivery. Generally, the card is built before the third trimester of pregnancy, and you need to bring your ID card to the local medical institution or maternal and child health institution to apply for the card, as the policy varies from place to place, generally the pregnancy card is voluntary.