The obstetrics department divides the whole pregnancy into 3 stages, namely early pregnancy, middle pregnancy and late pregnancy, of which the first week to the end of the 13th week of pregnancy is the early pregnancy. Early pregnancy contains the period when the fertilized egg is laid, and it is also a critical period for embryo formation, organ differentiation and fetal neurovascular development, during which the embryo is not yet stable in the uterine cavity and is easily affected by external factors, which can lead to miscarriage, thus it is also called the danger period. When the pregnancy reaches 14 weeks, the fetus is well developed and more stable in the uterine cavity. In the middle and late stages of pregnancy the uterine cavity is no longer filled with embryonic tissue, but with fetus. These two periods are important for the development and maturation of the fetus’ internal organs. During pregnancy, you should regularly go to the obstetrics department for maternity, prohibit sexual intercourse in early pregnancy, avoid overworking, keep a good mind, develop a regular and good life routine, and pay attention to balanced supplementation.