RT Journal Article SR Electronic T1 Use of herbal products in pregnancy: harms are reported but the benefit to harm balance is uncertain JF BMJ Evidence-Based Medicine JO BMJ EBM FD BMJ Publishing Group Ltd SP bmjebm-2019-111240 DO 10.1136/bmjebm-2019-111240 A1 Igho Onakpoya YR 2019 UL http://ebm.bmj.com/content/early/2019/08/23/bmjebm-2019-111240.abstract AB