Outcome or subgroup	Studies	Participants	Statistical method	Effect estimate
6.1 Neural tube defects	2	248,056	Risk Ratio (M‐H, Random, 95% CI)	0.53 [0.41, 0.67]
6.1.1 Non RCTs	2	248,056	Risk Ratio (M‐H, Random, 95% CI)	0.53 [0.41, 0.67]
6.2 Neural tube defects	2	248,056	Risk Ratio (M‐H, Random, 95% CI)	0.53 [0.41, 0.67]
6.2.1 400 μg/0.4 mg	1	247,831	Risk Ratio (M‐H, Random, 95% CI)	0.53 [0.42, 0.68]
6.2.2 5 mg	1	225	Risk Ratio (M‐H, Random, 95% CI)	0.14 [0.01, 2.50]