Security, also known as ritodrine hydrochloride, this drug has no side effects on the fetus, is a more effective drug to inhibit contractions, clinical commonly used in pregnant women with preterm labor. Ritodrine hydrochloride can bind with the β2-adrenergic receptors on the membrane of uterine smooth muscle cells, inhibit smooth muscle contraction, and inhibit contractions to achieve the effect of fetal preservation. It generally has no effect on the fetus, but pregnant women who have a combination of heart disease, severe high blood pressure, uncontrolled diabetes mellitus, etc., should be used with caution or not. In the process of use, we should pay attention to observe the changes of heart rate, blood pressure and contraction, heart rate is too fast than 120 times per minute, need to slow down the drip rate, reduce the dosage, more than 140 times per minute need to stop using the drug. If chest pain occurs, stop the medication immediately. During the period, pay attention to blood glucose test, pay attention to potassium supplementation, and consult a doctor if necessary. If there are other problems, it is recommended to consult a professional doctor for guidance.