The incidence of obstetric brachial plexus palsy (OBPP) has been variously estimated at between 1.6 and 5.1 per 1000 live births in developed countries. In western Sweden, the incidence increased from 1.7 to 2.7 per 1000 live births between 1987 and 1997. Many children recover completely, but most studies have had methodological limitations. Now (Anna-Lena Lagerkvist and colleagues. Dev Med Child Neurol 2010;52:529–34; see also Commentary, ibid: 502), a prospective, population-based …