Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Adverse effects
Systematic review	40 women Data from 1 RCT	Proportion of women who had a premature birth 2/20 (10%) with low-dose aspirin (50–81 mg/day) 0/20 (0%) with control	RR 5.0 95% CI 0.3 to 98.0 This analysis was likely to have been underpowered to detect differences between groups		Not significant
Systematic review	125 women 3 RCTs in this analysis	Proportion of women who had fetal growth restriction 4/64 (6%) with low-dose aspirin (50–81 mg/day) 8/61 (13%) with control	RR 0.6 95% CI 0.2 to 1.7 This analysis was likely to have been underpowered to detect differences between groups		Not significant