The time of how long a pregnant woman with preterm labor will give birth after birth control is not certain, if the symptoms improve, and even wait until the full term of pregnancy delivery, if the symptoms worsen, delivery within a few hours is also possible. Preterm labor is usually referred to 28-37 weeks of pregnancy contractions or a little vaginal bleeding, need to be appropriate rest, Ritodrine to inhibit contractions, less than 32 weeks of pregnant women given magnesium sulfate to protect the fetal cerebral nerve, less than 35 weeks of pregnant women given dexamethasone to promote fetal lung maturation. If the symptoms improve or decrease after treatment, labor can even be delayed until full term, i.e. 37 weeks. Generally, after 34 weeks of pregnancy, there is no treatment to protect the fetus, but to closely observe the progress of labor and pay attention to the safety of the mother and fetus. If the symptoms of preterm labor worsen and develop into preterm labor, then preterm labor cannot be suppressed, and it is necessary to stop the treatment of preterm labor to prevent serious complications during and after labor.