| Study | Reason for exclusion |
|---|---|
| Beall 1985 | The intervention is the use of IV, not oral, tocolytic therapy. |
| Besinger 1991 | The trial compared IV and oral ritodrine to oral indomethacin. |
| Cabero 1988 | The women in this study were randomised to oral betamimetics for treatment of an initial episode of threatened preterm labour not for maintenance therapy. |
| Caritis 1984 | Study compared 2 betamimetic agents (terbutaline and ritodrine) given intravenously rather than orally. |
| Forster 1987 | The women in this study were randomised to oral betamimetics for treatment of an initial episode of threatened preterm labour not for maintenance therapy. |
| Garite 1987 | Arrest of premature labour was randomised, but use of oral ritodrine as maintenance therapy was not. |
| Hagay 1994 | The trial compares 2 formulations of the same betamimetic tocolytic (ritodrine), rather than comparing a betamimetic with an alternative therapy. |
| Ingemarsson 1976 | The trial compared IV and oral terbutaline to IV and oral placebo. |
| Larsen 1986 | The study assessed the effect of IM ritodrine on the arrest of premature labour, as well as the effect of oral ritodrine as maintenance therapy. The women had thus received "other treatment" in addition to the oral betamimetic. |
| Levy 1985 | The population studied are women with premature rupture of membranes, not preterm labour. |
| Martin 1988 | The women in this study were randomised to the ritodrine and magnesium gluconate groups according to attending staff preference. Thus it is not a RCT. |
| Penney 1980 | Outcomes reported by the study were not those specified in the review protocol. |
| Smit 1983 | The women in this study were randomised to oral betamimetics for treatment of an initial episode of threatened preterm labour not for maintenance therapy. |
| Spellacy 1979 | The study assessed the effect of IV and IM ritodrine as well as the effect of oral ritodrine as maintenance therapy. |
| W‐De Casparis 1971 | The trial compared IV and oral ritodrine to IV and oral placebo. |
| Weisbach 1986 | The women in this study were randomised to oral betamimetics for treatment of an initial episode of threatened preterm labour not for maintenance therapy. |
| Wenstrom 1997 | The women in this study were randomised to oral betamimetics for treatment of an initial episode of threatened preterm labour not for maintenance therapy. |
IM: intramuscular IV: intravenous RCT: randomised controlled trial