这篇论文说有统计数字显示1%的破腹产婴儿有伤害

http://www.ncbi.nlm.nih.gov/pubmed/17012450

RESULTS:
A total of 37,110 cesarean deliveries were included in the registry, and 418 (1.1%) had an identified fetal injury. The most common injury was skin laceration (n = 272, 0.7%). Other injuries included cephalohematoma (n = 88), clavicular fracture (n = 11), brachial plexus (n = 9), skull fracture (n = 6), and facial nerve palsy (n = 11).