Methods	RCT.
Participants	Singleton (and 3 twin) gestations; uterine contractions or symptoms suggestive of preterm labor at 24 to 33 6/7 weeks. N = 100
Interventions	TVU CL knowledge or not (the control group did receive TVU CL, but results were blinded to managing physicians) Time TVU CL results available: not specified. Protocol for TVU knowledge group: yes.
Outcomes	Primary: time from initial evaluation to discharge.
Notes	Intention to treat; 97% singletons; protocol for management of TVU CL group, which included management based on FFN for women with CL 20 to 29 mm Short TVUCL ( < 20mm): 11/51 (22%) in knowledge group; 7/49 (15%) in the control group
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer-generated random numbers.
Allocation concealment (selection bias)	Low risk	Numbered, sealed opaque envelopes.
Blinding (performance bias and detection bias) All outcomes	High risk	Women and physicians knew which group was randomized to ‘knowledge’ or ‘no knowledge’
Incomplete outcome data (attrition bias) All outcomes	Low risk	Intention-to-treat analyses.
Selective reporting (reporting bias)	Low risk	Primary outcome time from evaluation to discharge.