Use of calcium channel antagonists for preterm labor.

There is dispute in the United States about what should be the first line of tocolytics for preterm labor. In Europe, the initial choice to prevent preterm birth is a calcium channel antagonist (CCA). Randomized studies have noted that CCAs are as efficacious as other tocolytics and a meta-analysis concluded that use of these blockers is associated with significantly lower likelihood of delivery before 34 weeks and reduction in rate of respiratory distress syndrome, intraventricular hemorrhage, and necrotizing enterocolitis. It is time that CCAs become the preferred tocolytics in the United States.