Timing of high-dose folic acid supplementation in the periconceptional period among women taking antiseizure medications and risk of major congenital anomalies: a target trial emulation

Initiation of high-dose folic acid in the 12 weeks before pregnancy was associated with a reduced risk of MCA in offspring of women using ASMs while initiation in the 12 weeks after pregnancy onset was not. RESEARCH PROTOCOL REGISTRATION: https://osf.io/vph2n/?view_only=c9361e4996eb4c4da32fc878f2fbf5b9.