<prompt> Drug used to prevent premature birth includes all except-RitodrinErgometrineMagnesium sulfateAtosiban  <response>: Ans. is bi.e., Ergometrine Tocolyticso These drugs are used to decrease uterine contractions to delay the labour when there is premature onset of contraction. Tocolytic drugs are b2-agonists ritodrin, magnesium sulfate, ethyl alcohol, progesterone, diazoxide, calcium channel blocker nifedipine, atosiban oxytocin antagonist, NSAIDs and nitrate. 