The 37~42 weeks baby is already a full-term mature child. 38 weeks baby, if there is no disease, develops close to maturity in the pregnant woman’s stomach, and all organs have been formed, with good viability and high survival rate after birth. The length of a 38-week-old baby is about 47cm, the length of the top hip is about 34cm, and the weight is about 3,000g. There is more subcutaneous fat, the body is rounded, a layer of fine downy hairs and most of the white fetal fat covering the body of the fetus is gradually falling off, and the facial folds are disappearing. Finger (toe) nails have reached the end of fingers (toes), and fetal hair has grown, but the exact length and color are related to many factors. In addition, the circulatory, respiratory, and digestive organs, led by the heart, lungs, and liver, have all been formed, and have acquired the ability to survive independently outside the mother’s body. To know specifically what kind of baby is in the belly at 38 weeks can be seen through ultrasound imaging.