Tocolysis of preterm contractions does not improve preterm delivery rate or perinatal outcomes.

To determine whether hospital admission and parenteral tocolysis of patients with threatened preterm labor results in a decreased preterm delivery rate and improved perinatal outcome, we performed a prospective cohort study comparing tocolytic treatment versus no tocolytic treatment. Women between 20 and 37 weeks' gestation who presented with at least eight uterine contractions per hour and a cervical examination <2 cm dilated, <80% effaced, and no cervical change over a 2-hr period were entered into the study. Exclusion criteria included cervical change, multiple gestation, chorioamnionitis, rupture of membranes, placenta previa or abruption, undiagnosed vaginal bleeding, and prior tocolytic therapy in the current pregnancy. Seventy-five patients were admitted to the hospital for tocolysis (tocolysis cohort) and 81 were observed and discharged to home (observation cohort). There was no significant difference in mean gestational age at delivery, mean birth weight, or in preterm delivery rate between the two cohorts. Four of the eight women in the observation cohort who delivered preterm had a history of preterm delivery. We conclude that discharging women with preterm contractions without objective evidence of labor does not result in an increase in preterm births. More importantly, tocolysis did not decrease the preterm delivery rate in this cohort.