Matijevic 2006.

Methods	Randomisation was by a computer‐generated table of random numbers. Allocation concealment through sealed opaque envelopes. Blinding: women blinded to allocation through use of a placebo. Losses to follow up: none reported.
Participants	120 women who met the following inclusion criteria: singleton pregnancy; gestational age 24‐34 weeks; > 5 contractions per hour for 2 hours; modified bishop score > 3.
Interventions	Following successful parenteral tocolysis, women were randomly assigned to ritodrine (80 mg 3 times per day) or placebo.
Outcomes	Preterm birth < 34 weeks; preterm birth < 37 weeks; preterm birth in 72 hours; infant birthweight; perinatal mortality; NICU admission; Apgar score < 7 at 5 minutes; mechanical ventilation; maternal side effects (pulmonary oedema, tremor, tachycardia, shortness of breath).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random number table.
Allocation concealment (selection bias)	Low risk	Sealed opaque envelopes.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not stated.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No reported losses to follow‐up.
Selective reporting (reporting bias)	Unclear risk	Unable to assess.
Other bias	Low risk