Letters Smart cards are expensive and easily damaged BMJ 1995; 310 doi: https://doi.org/10.1136/bmj.310.6986.1066c (Published 22 April 1995) Cite this as: BMJ 1995;310:1066 Article Related content Metrics Responses Peer review Related articles Editorial Assessing the consequences of changing childbirth Published: 21 January 1995; BMJ 310 doi:10.1136/bmj.310.6973.144