Methods
milk and blood specimen
The full study protocol is published elsewhereThe primary phase of the study included evaluation of folate status during pregnancy; participants had the option to continue to the postpartum study phase, which included obtaining separate informed consent at the endline visit (occurred 16-weeks after baseline) and continued supplementation until ~ 1 week postpartum for collection of a human milk and blood specimen. Adherence to daily folate supplementation throughout the study was assessed with capsule counts. The sample size was chosen for the primary study phase