1. Estadística IneIN. Estadística de nacimientos. Movimiento natural de la población [Internet]. [cited 2018 Jun 5]. Available from:
http://www.ine.es/dyngs/INEbase/es/categoria.htm?c=Estadistica_P&cid=1254735573002
2. Statista: the statistics portal. Vaginal and C-section deliveries in US 2013 by risk | Statistic [Internet]. Hamburg: Statista. 2016 [cited 2018 Jun 5]. Available from:
https://www.statista.com/statistics/633106/rate-of-total-deliveries-in-us-by-risk-level-and-delivery-type/
3. National Health System. NHS Digital. NHS Maternity Statistics, England 2016-17 [Internet]. London. 2017 [cited 2018 Jun 5]. Available from:
https://digital.nhs.uk/data-and-information/publications/statistical/nhs-maternity-statistics/2016-17
4. Observatorio de salud de las mujeres. Informe sobre la Atención al Parto y Nacimiento en el Sistema Nacional de Salud. Estrategia de atención al parto normal en el Sistema Nacional de Salud. [Internet]. 2015 [cited 2018 Jul 31]. Available from:
https://www.msssi.gob.es/organizacion/sns/planCalidadSNS/pdf/InformeFinalEAPN_revision8marzo2015.pdf
5. Petz B. Birth & Death Rates | Ecology Global Network [Internet]. Ecology Communications Group, Inc. (ECG). 2010 [cited 2018 Aug 1]. Available from:
http://www.ecology.com/birth-death-rates/