Comparison 1. Aspirin versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Live birth	1	40	Risk Ratio (M‐H, Fixed, 95% CI)	0.94 [0.71, 1.25]
1.2 Pre‐eclampsia	1	33	Risk Ratio (M‐H, Fixed, 95% CI)	1.06 [0.25, 4.52]
1.3 Adverse events in the mother	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.3.1 Bleeding	1	40	Risk Ratio (M‐H, Fixed, 95% CI)	1.29 [0.60, 2.77]
1.4 Preterm delivery of a live infant	1	33	Risk Ratio (M‐H, Fixed, 95% CI)	5.29 [0.27, 102.49]
1.5 Intrauterine growth restriction	1	33	Risk Ratio (M‐H, Fixed, 95% CI)	0.27 [0.03, 2.13]
1.6 Adverse events in the child	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.6.1 Congenital malformations	1	33	Risk Ratio (M‐H, Fixed, 95% CI)	1.06 [0.07, 15.60]
1.7 Pregnancy loss	1	40	Risk Ratio (M‐H, Fixed, 95% CI)	1.33 [0.34, 5.21]