In general, fetal lung maturation injections should be given for 48 hours and 72 hours for twin pregnancies, but the exact number of days should be decided by the doctor. Fetal lung maturation injections are given to promote the maturation of the fetal lungs and are usually used when the mother is in preterm labor to prevent the fetus from developing immature lungs and being unable to adapt to the external environment, which can lead to conditions such as respiratory distress syndrome. It is important to note that although lung promotion injections are effective, they need to be used under strict indications and under the guidance of a medical professional. The lung promotion injection does not mean immediate delivery, if the pregnant woman is in good condition, she can wait for natural delivery. At the same time, if the gestational week has reached 34 weeks, or 35 weeks in the case of gestational diabetes, the lungs of the fetus are usually already mature and capable of breathing on their own, so there is no need for the lung promotion injection. After the injection, the pregnant woman should pay attention to the fetal heartbeat and fetal movement. Pay attention to rest, ensure sufficient sleep, and try to avoid anxiety, tension, depression and other emotions, so as not to affect the fetal development.