As part of the World Health Organization’s (WHO) normative work on supporting evidence-informed policies and practices, WHO updated the recommendation on Multiple Micronutrient Supplementation (MMS) on the basis of additional trials published after the release of the 2016 Antenatal Care (ANC) guidelines. For the updated recommendation, data on effectiveness were derived from the updated Cochrane review. The resulting evidence on effectiveness was found to be largely similar to that evaluated during the 2016 guidelines development process, showing an average 12% (9%–14%) reduction in low birth weight with MMS but little difference in effects on low birth weight’s component parts (preterm birth or being small for gestational age).