Tocolysis for repeat external cephalic version in breech presentation at term: a randomised, double-blinded, placebo-controlled trial.

BACKGROUND External cephalic version (ECV) reduces the incidence of breech presentation at term and caesarean section for non-cephalic births. Tocolytics may improve success rates, but are time consuming, may cause side effects and have not been proven to alter caesarean section rates. The aim of this trial was to determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt. OBJECTIVE To determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt. DESIGN Randomised, double-blinded, placebo-controlled trial. SETTING UK teaching hospital. POPULATION One hundred and twenty-four women with a breech presentation at term who had undergone an unsuccessful attempt at ECV. METHODS Relative risks with 95% confidence intervals for categorical variables and a t test for continuous variables. Analysis was by intention to treat. MAIN OUTCOME MEASURES Incidence of cephalic presentation at delivery. Secondary outcomes were caesarean section and measures of neonatal and maternal morbidity. RESULTS The use of tocolysis for a repeat attempt at ECV significantly increases the incidence of cephalic presentation at delivery (RR 3.21; 95% CI 1.23-8.39) and reduces the incidence of caesarean section (RR 0.33; 95% CI 0.14-0.80). The effects were most marked in multiparous women (RR for cephalic presentation at delivery 9.38; 95% CI 1.64-53.62). Maternal and neonatal morbidity remain unchanged. CONCLUSIONS The use of tocolysis increases the success rate of repeat ECV and reduces the incidence of caesarean section. A policy of only using tocolysis where an initial attempt has failed leads to a relatively high success rate with minimum usage of tocolysis.