Pulmonary stimulating injections, which are dexamethasone, betamethasone, and other, glucocorticoid drugs, generally dexamethasone is preferred. These drugs, which have the function of promoting the maturation of fetal alveoli, are used to promote lung injection, usually when there are obvious symptoms of prematurity, mainly to promote the development and maturation of fetal lungs and improve the survival rate after birth. Although the drugs used are of the glucocorticoid class, the use of lung promotion injections for fetuses with clear indications does not generally produce significant adverse effects because the number of uses is relatively small and the duration is relatively short. After the use of the lung promoter injection, usually around two to three times, the effect will be noticeable and the alveoli will develop significantly. Since this drug, is mainly used when there are symptoms of preterm labor, it does not matter after the injection, even if preterm labor does not occur.