Gibson 1998.

Study characteristics
Methods	RCT (3 arms).
Participants	17 women were randomised. Setting: authors from Glasgow, UK. Study dates: not reported. Inclusion criteria: women undergoing a caesarean section; either an emergency caesarean section or with other risk factors for VTE. Exclusion criteria: not reported.
Interventions	Group 1 (n = 6): LMWH (enoxaparin) 20 mg once daily. Group 2 (n = 5): LMWH (enoxaparin) 40 mg once daily. Group 3 (n = 6): UFH 7500 IU every 12 hours. Intervention started after caesarean section, duration of intervention not stated.
Outcomes	Review outcomes reported: symptomatic thromboembolic events; symptomatic PE; symptomatic DVT; bleeding episodes (reports "haemorrhagic event"). Other outcomes reported: anti‐Xa activity.
Notes	3‐way randomisation (UFH/20 mg enoxaparin/40 mg enoxaparin). 2 enoxaparin groups combined for inclusion in the review analysis. Funding sources: not reported. Declarations of interest: not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as "women were randomised".
Allocation concealment (selection bias)	Unclear risk	Not stated.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not feasible.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No detail of blinding of outcome assessors.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No losses to follow‐up stated; no detail regarding exclusions.
Selective reporting (reporting bias)	Unclear risk	No trial protocol to confidently assess selective reporting; furthermore data for many relevant clinical outcomes was not reported.
Other bias	Unclear risk	Insufficient information to assess whether an important risk of bias exists.