Of the 256 articles evaluated, we abstracted data from 60 first-line and 15 maintenance studies.
Of these, 16 first-line and 8 maintenance studies met more stringent requirements for meta-analyses. Studies
of first-line tocolysis (grade Fair) reveal a mixed outcome pattern with small improvement in pregnancy
prolongation and birth at term relative to placebo. Data were insufficient to show directly a beneficial effect on
neonatal morbidity or mortality. Ethanol was less beneficial than, and β-mimetics were not superior to, other
tocolytic options. Maintenance tocolytics (grade Poor) showed no improvements in birth or infant outcomes
relative to placebo; these results were confirmed through meta-analysis. In contrast to other tocolytic treatments,
maternal harms from β-mimetics were rated High; all tocolytics were rated as Low risk for short-term
neonatal harms