In general, the actual development of the baby is based on the results of the ultrasound. However, since there are obvious individual differences in the development of the fetus in the late stages of pregnancy, 37 weeks of pregnancy but 35 weeks of ultrasound counts as a full-term baby needs to be assessed according to the various values of the obstetric examination of the fetus. As long as the values are within the normal range, it can be counted as a full-term child; if the deviation is large, consider whether there is maternal nutritional deficiencies, placental hypoplasia and other problems caused by fetal developmental delay: 1, maternal nutritional deficiencies: the development of the fetus in mid-late pregnancy requires a lot of nutrients, vitamins, minerals, and other deficiencies may cause fetal development to slow down, for example, the lack of vitamin D or calcium will result in the development of fetal bone insufficiency For example, vitamin D or calcium deficiency may cause fetal bone failure, and iron deficiency may cause slow fetal development. Therefore, pregnant women need reasonable diet, adequate nutrition, timely supplementation can generally alleviate the symptoms; 2, placental hypoplasia: placental hypoplasia will cause the fetus can not absorb adequate nutrients, and even distress. At this time, it is necessary to carry out fetal heart monitoring, placental function and other tests to assess the state of the placenta, according to the specific circumstances, under the advice of the doctor to decide whether to continue the pregnancy.