Fertility-preserving drugs to suppress contractions in the 28th week of pregnancy include Ritodrine, Atosiban, and magnesium sulfate. It is recommended to choose the appropriate drug according to the difference of specific situations under the judgment of obstetrics and gynecology professional doctors. 1. Ritodrine: Ritodrine belongs to β-adrenergic receptor agonist, which inhibits uterine smooth muscle contraction by binding to β-receptor of uterine smooth muscle cell membrane and decreasing the activity of uterine muscle contractile protein. The main adverse effects are cardiovascular manifestations, such as increased heart rate, sweating and flushing. 2. Atosiban: It is suitable for pregnant women who fulfill the conditions of 24~33 weeks of gestation and normal fetal heart rate. Contraindications include intrauterine fetal growth retardation, eclampsia, placenta previa and other conditions. Adverse reactions are generally mild, nausea is more common. 3. Magnesium Sulfate: It should not be used simultaneously with β-adrenergic receptor agonists, such as Ritodrine, in the treatment of fetal preservation, otherwise it is likely to cause adverse cardiovascular reactions. It is recommended to use birth control drugs to inhibit contractions under the guidance of a professional doctor at 28 weeks of pregnancy, do not use drugs or change the dosage of drugs without authorization, so as not to cause serious effects on pregnant women.