The normal gestation period is 280 days, or 40 weeks. Medically, 4 weeks is considered as 1 gestational month, so 3 months of pregnancy is 12 weeks. Usually, the embryonic condition is not very stable before the 3rd month of pregnancy, and it is easy to have a preterm miscarriage. After the third month of pregnancy, the fetus is basically stable and the probability of miscarriage decreases significantly. The human chorionic gonadotropin level of pregnant women also tends to be stable and can be maintained at a relatively constant state, and early pregnancy reactions such as nausea, vomiting and anorexia will also improve significantly or even subside, and the fetus will enter a stage of rapid growth and development. At this time, pregnant women should supplement nutrition in a timely manner, and can choose pregnant women’s milk powder and pay attention to calcium supplementation according to medical advice. In addition, pregnant women can do aerobic exercise to prevent excessive weight gain. At the same time, pay attention to balanced nutrition, eat more food rich in high quality protein, as well as fresh vegetables and fruits to ensure an adequate supply of nutrients to promote the normal growth and development of the fetus.