Carlan 1997

Methods	RCT.
Participants	Singleton gestations; PPROM; 24 to 34 weeks. N = 92.
Interventions	TVU CL or not (the control group did not receive TVU CL). Time TVU CL results available: not specified. Protocol for TVU knowledge group: no.
Outcomes	Primary: maternal infection.
Notes	Intention‐to‐treat; only singletons; PPROM; no protocol (really a safety study for TVU CL in PPROM women). Short TVU CL (< 25 mm): 14/45 (31%) in knowledge group; not done in other group.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomly‐generated assignment."
Allocation concealment (selection bias)	Low risk	"Randomly‐generated" assignments in sealed envelopes.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Study group had weekly US while controls had none.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	1% explained.
Selective reporting (reporting bias)	Low risk	Primary outcome was chorioamnionitis. All other outcomes reported.
Other bias	Unclear risk	No baseline characteristics table.