Combined Uterorelaxant Effect of Magnesium Sulfate and Terbutaline: Studies on Late Pregnant Rat Uteri In Vitro and In Vivo

(Acta Obstet Gynecol Scand. 2023;102:457–464) Preterm birth is a common and impactful complication of pregnancy and is defined as the delivery of a fetus between 20 and 37 weeks of gestation. It can lead to further complications and even developmental problems for the child that can be long term. Standard treatment for symptoms of preterm labor involves tocolytic drugs to stop contractions and delay delivery long enough for interventions to occur, minimizing effects on the infant. Although many different drugs are used, the efficacy and side effects of many are not well characterized or understood. This study was designed to assess the effectiveness and side effects of a combination of drugs: β2-agonist terbutaline and magnesium sulfate (MgSO4). This was done by examining the combined administration of the drugs in an isolated organ bath and performing in vivo smooth muscle electromyographic studies in pregnant rats.