1. Global, regional, and national levels of maternal mortality, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015;Kassebaum;Lancet.,2016
2. Indicadores de Salud 2017. Evolución de los indicadores del estado de salud en España y su magnitud en el contexto de la Unión Europea,2017
3. Effects and safety of periconceptional oral folate supplementation for preventing birth defects;De-Regil;Cochrane Database Syst Rev.,2015
4. The Guide to clinical Preventive Service 2014. Recommendations of the U.S. Preventive Service Task Force. [consultado 1 Feb 2020]. Disponible en: https://www.uspreventiveservicestaskforce.org/uspstf/topic_search_results?topic_status=P&gender%5B%5D=14&searchterm=
5. Folic Acid Supplementation for the Prevention of Neural Tube Defects;Viswanathan;JAMA.,2017