At 38 and 39 weeks of pregnancy, the fetus has matured, and the difference between babies born at this time is mainly manifested in the level of weight and immunity. 1. weight level: because the fetus in 38 and 39 weeks of pregnancy belongs to the rapid growth period, so the baby born in 39 weeks tends to weigh more than the baby born in 38 weeks. 2. immunity level: babies born at 39 weeks have more mature development of liver, lungs and brain, so their immunity is stronger than babies born at 38 weeks. After the birth of the baby, parents should pay attention to observe the baby’s signs and symptoms, if there is any abnormality, they should go to the hospital in time and take appropriate treatment measures under the guidance of specialists.